{
  "title": "Unit Conversion Factors: A Verified Reference (2026 Edition)",
  "version": "1.0.0",
  "released": "2026-06-03",
  "license": "CC-BY-4.0",
  "license_url": "https://creativecommons.org/licenses/by/4.0/",
  "citation": "Gizmoop Editorial Team (2026). Unit Conversion Factors: A Verified Reference (2026 Edition, v1.0). https://gizmoop.com/research/unit-conversions",
  "publisher": "Gizmoop",
  "publisher_url": "https://gizmoop.com",
  "contact": "gizmoopofficial@gmail.com",
  "url": "https://gizmoop.com/research/unit-conversions",
  "download_url": "https://gizmoop.com/research/unit-conversions-2026-v1.json",
  "total_records": 165,
  "categories": [
    "Length and distance",
    "Mass and weight",
    "Volume",
    "Area",
    "Temperature",
    "Speed and velocity",
    "Energy",
    "Power",
    "Pressure",
    "Time",
    "Data storage"
  ],
  "records": [
    {
      "id": "len-m-ft",
      "category": "Length and distance",
      "from_unit": "metre (m)",
      "to_unit": "foot (ft)",
      "factor": "3.28084",
      "formula_note": "ft = m / 0.3048",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-m-in",
      "category": "Length and distance",
      "from_unit": "metre (m)",
      "to_unit": "inch (in)",
      "factor": "39.3701",
      "formula_note": "in = m / 0.0254",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-m-yd",
      "category": "Length and distance",
      "from_unit": "metre (m)",
      "to_unit": "yard (yd)",
      "factor": "1.09361",
      "formula_note": "yd = m / 0.9144",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-km-mi",
      "category": "Length and distance",
      "from_unit": "kilometre (km)",
      "to_unit": "mile (mi)",
      "factor": "0.621371",
      "formula_note": "mi = km / 1.609344",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-km-ft",
      "category": "Length and distance",
      "from_unit": "kilometre (km)",
      "to_unit": "foot (ft)",
      "factor": "3280.84",
      "formula_note": "ft = km x 1000 / 0.3048",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-ft-m",
      "category": "Length and distance",
      "from_unit": "foot (ft)",
      "to_unit": "metre (m)",
      "factor": "0.3048",
      "formula_note": "m = ft x 0.3048",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-ft-cm",
      "category": "Length and distance",
      "from_unit": "foot (ft)",
      "to_unit": "centimetre (cm)",
      "factor": "30.48",
      "formula_note": "cm = ft x 30.48",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-ft-in",
      "category": "Length and distance",
      "from_unit": "foot (ft)",
      "to_unit": "inch (in)",
      "factor": "12",
      "formula_note": "1 ft = 12 in by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-in-cm",
      "category": "Length and distance",
      "from_unit": "inch (in)",
      "to_unit": "centimetre (cm)",
      "factor": "2.54",
      "formula_note": "cm = in x 2.54",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-in-m",
      "category": "Length and distance",
      "from_unit": "inch (in)",
      "to_unit": "metre (m)",
      "factor": "0.0254",
      "formula_note": "m = in x 0.0254",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-mi-km",
      "category": "Length and distance",
      "from_unit": "mile (mi)",
      "to_unit": "kilometre (km)",
      "factor": "1.609344",
      "formula_note": "km = mi x 1.609344",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-mi-m",
      "category": "Length and distance",
      "from_unit": "mile (mi)",
      "to_unit": "metre (m)",
      "factor": "1609.344",
      "formula_note": "m = mi x 1609.344",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-mi-ft",
      "category": "Length and distance",
      "from_unit": "mile (mi)",
      "to_unit": "foot (ft)",
      "factor": "5280",
      "formula_note": "1 mi = 5280 ft by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-yd-m",
      "category": "Length and distance",
      "from_unit": "yard (yd)",
      "to_unit": "metre (m)",
      "factor": "0.9144",
      "formula_note": "m = yd x 0.9144",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-yd-ft",
      "category": "Length and distance",
      "from_unit": "yard (yd)",
      "to_unit": "foot (ft)",
      "factor": "3",
      "formula_note": "1 yd = 3 ft by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-nm-m",
      "category": "Length and distance",
      "from_unit": "nautical mile",
      "to_unit": "metre (m)",
      "factor": "1852",
      "formula_note": "m = nm x 1852",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-nm-mi",
      "category": "Length and distance",
      "from_unit": "nautical mile",
      "to_unit": "mile (mi)",
      "factor": "1.15078",
      "formula_note": "mi = nm x 1.15078",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-fathom-m",
      "category": "Length and distance",
      "from_unit": "fathom",
      "to_unit": "metre (m)",
      "factor": "1.8288",
      "formula_note": "1 fathom = 6 ft (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-furlong-m",
      "category": "Length and distance",
      "from_unit": "furlong",
      "to_unit": "metre (m)",
      "factor": "201.168",
      "formula_note": "1 furlong = 1/8 mi (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-angstrom-m",
      "category": "Length and distance",
      "from_unit": "angstrom (A)",
      "to_unit": "metre (m)",
      "factor": "1e-10",
      "formula_note": "m = A x 1e-10 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-ly-m",
      "category": "Length and distance",
      "from_unit": "light-year (ly)",
      "to_unit": "metre (m)",
      "factor": "9.4607304725808e15",
      "formula_note": "distance light travels in 1 Julian year in vacuum (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-au-m",
      "category": "Length and distance",
      "from_unit": "astronomical unit (AU)",
      "to_unit": "metre (m)",
      "factor": "149597870700",
      "formula_note": "m = AU x 149597870700 (IAU 2012 exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-pc-m",
      "category": "Length and distance",
      "from_unit": "parsec (pc)",
      "to_unit": "metre (m)",
      "factor": "3.0856775814913673e16",
      "formula_note": "pc = 648000 / pi AU (IAU 2015 exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-marla-m2",
      "category": "Length and distance",
      "from_unit": "marla (Pakistan)",
      "to_unit": "square metre (m^2)",
      "factor": "25.2929",
      "formula_note": "1 marla = 272.25 sq ft (Pakistan standard)",
      "is_exact": false,
      "source_name": "Pakistan land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "len-kanal-m2",
      "category": "Length and distance",
      "from_unit": "kanal (Pakistan)",
      "to_unit": "square metre (m^2)",
      "factor": "505.857",
      "formula_note": "1 kanal = 20 marla (Pakistan standard)",
      "is_exact": false,
      "source_name": "Pakistan land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-kg-lb",
      "category": "Mass and weight",
      "from_unit": "kilogram (kg)",
      "to_unit": "pound (lb)",
      "factor": "2.20462",
      "formula_note": "lb = kg / 0.45359237",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-kg-oz",
      "category": "Mass and weight",
      "from_unit": "kilogram (kg)",
      "to_unit": "ounce (oz)",
      "factor": "35.27396",
      "formula_note": "oz = kg x 35.27396",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-lb-kg",
      "category": "Mass and weight",
      "from_unit": "pound (lb)",
      "to_unit": "kilogram (kg)",
      "factor": "0.45359237",
      "formula_note": "kg = lb x 0.45359237 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-lb-g",
      "category": "Mass and weight",
      "from_unit": "pound (lb)",
      "to_unit": "gram (g)",
      "factor": "453.59237",
      "formula_note": "g = lb x 453.59237 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-oz-g",
      "category": "Mass and weight",
      "from_unit": "ounce (oz)",
      "to_unit": "gram (g)",
      "factor": "28.349523125",
      "formula_note": "g = oz x 28.349523125 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-g-oz",
      "category": "Mass and weight",
      "from_unit": "gram (g)",
      "to_unit": "ounce (oz)",
      "factor": "0.0352740",
      "formula_note": "oz = g / 28.349523125",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-g-grain",
      "category": "Mass and weight",
      "from_unit": "gram (g)",
      "to_unit": "grain (gr)",
      "factor": "15.4324",
      "formula_note": "gr = g x 15.4324",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-tonne-kg",
      "category": "Mass and weight",
      "from_unit": "tonne (metric ton)",
      "to_unit": "kilogram (kg)",
      "factor": "1000",
      "formula_note": "kg = t x 1000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-short-ton-kg",
      "category": "Mass and weight",
      "from_unit": "short ton (US)",
      "to_unit": "kilogram (kg)",
      "factor": "907.18474",
      "formula_note": "2000 lb x 0.45359237",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-long-ton-kg",
      "category": "Mass and weight",
      "from_unit": "long ton (UK)",
      "to_unit": "kilogram (kg)",
      "factor": "1016.0469088",
      "formula_note": "2240 lb x 0.45359237",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-stone-kg",
      "category": "Mass and weight",
      "from_unit": "stone (st)",
      "to_unit": "kilogram (kg)",
      "factor": "6.35029",
      "formula_note": "1 st = 14 lb (exact)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-stone-lb",
      "category": "Mass and weight",
      "from_unit": "stone (st)",
      "to_unit": "pound (lb)",
      "factor": "14",
      "formula_note": "1 st = 14 lb by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-grain-g",
      "category": "Mass and weight",
      "from_unit": "grain (gr)",
      "to_unit": "gram (g)",
      "factor": "0.06479891",
      "formula_note": "g = gr x 0.06479891 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-troy-oz-g",
      "category": "Mass and weight",
      "from_unit": "troy ounce (oz t)",
      "to_unit": "gram (g)",
      "factor": "31.1034768",
      "formula_note": "g = oz t x 31.1034768 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-troy-lb-g",
      "category": "Mass and weight",
      "from_unit": "troy pound (lb t)",
      "to_unit": "gram (g)",
      "factor": "373.2417216",
      "formula_note": "12 troy oz (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-carat-g",
      "category": "Mass and weight",
      "from_unit": "metric carat (ct)",
      "to_unit": "gram (g)",
      "factor": "0.2",
      "formula_note": "g = ct x 0.2 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-tola-g",
      "category": "Mass and weight",
      "from_unit": "tola",
      "to_unit": "gram (g)",
      "factor": "11.6638038",
      "formula_note": "1 tola = 12 masha (South Asian standard)",
      "is_exact": true,
      "source_name": "Indian sub-continent standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-maund-kg",
      "category": "Mass and weight",
      "from_unit": "maund (Pakistan)",
      "to_unit": "kilogram (kg)",
      "factor": "37.3242",
      "formula_note": "1 maund = 40 ser (Pakistan standard)",
      "is_exact": false,
      "source_name": "Pakistan trade standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-ser-kg",
      "category": "Mass and weight",
      "from_unit": "ser (Pakistan)",
      "to_unit": "kilogram (kg)",
      "factor": "0.93310",
      "formula_note": "1 ser = 80 tola (Pakistan standard)",
      "is_exact": false,
      "source_name": "Pakistan trade standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "mass-dram-g",
      "category": "Mass and weight",
      "from_unit": "dram (avoirdupois)",
      "to_unit": "gram (g)",
      "factor": "1.7718",
      "formula_note": "1 dram = 1/16 oz (avoirdupois)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-l-usgal",
      "category": "Volume",
      "from_unit": "litre (L)",
      "to_unit": "US gallon",
      "factor": "0.264172",
      "formula_note": "gal = L / 3.785411784",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-l-ukgal",
      "category": "Volume",
      "from_unit": "litre (L)",
      "to_unit": "UK gallon",
      "factor": "0.219969",
      "formula_note": "gal = L / 4.54609",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-l-usfloz",
      "category": "Volume",
      "from_unit": "litre (L)",
      "to_unit": "US fluid ounce",
      "factor": "33.814",
      "formula_note": "fl oz = L x 33.814",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-l-cm3",
      "category": "Volume",
      "from_unit": "litre (L)",
      "to_unit": "cubic centimetre (cm^3)",
      "factor": "1000",
      "formula_note": "L = 1000 cm^3 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-usgal-l",
      "category": "Volume",
      "from_unit": "US gallon",
      "to_unit": "litre (L)",
      "factor": "3.785411784",
      "formula_note": "L = gal x 3.785411784 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-usgal-floz",
      "category": "Volume",
      "from_unit": "US gallon",
      "to_unit": "US fluid ounce",
      "factor": "128",
      "formula_note": "1 US gal = 128 fl oz by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ukgal-l",
      "category": "Volume",
      "from_unit": "UK gallon",
      "to_unit": "litre (L)",
      "factor": "4.54609",
      "formula_note": "L = gal x 4.54609 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ukgal-floz",
      "category": "Volume",
      "from_unit": "UK gallon",
      "to_unit": "UK fluid ounce",
      "factor": "160",
      "formula_note": "1 UK gal = 160 fl oz by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-m3-l",
      "category": "Volume",
      "from_unit": "cubic metre (m^3)",
      "to_unit": "litre (L)",
      "factor": "1000",
      "formula_note": "L = m^3 x 1000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-m3-usgal",
      "category": "Volume",
      "from_unit": "cubic metre (m^3)",
      "to_unit": "US gallon",
      "factor": "264.172",
      "formula_note": "gal = m^3 x 264.172",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-m3-cuft",
      "category": "Volume",
      "from_unit": "cubic metre (m^3)",
      "to_unit": "cubic foot (cu ft)",
      "factor": "35.3147",
      "formula_note": "cu ft = m^3 x 35.3147",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-uscup-ml",
      "category": "Volume",
      "from_unit": "US cup",
      "to_unit": "millilitre (mL)",
      "factor": "236.588",
      "formula_note": "1 US cup = 8 US fl oz",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-usfloz-ml",
      "category": "Volume",
      "from_unit": "US fluid ounce",
      "to_unit": "millilitre (mL)",
      "factor": "29.5735",
      "formula_note": "mL = fl oz x 29.5735",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ukfloz-ml",
      "category": "Volume",
      "from_unit": "UK fluid ounce",
      "to_unit": "millilitre (mL)",
      "factor": "28.4131",
      "formula_note": "mL = fl oz x 28.4131",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ustbsp-ml",
      "category": "Volume",
      "from_unit": "US tablespoon",
      "to_unit": "millilitre (mL)",
      "factor": "14.7868",
      "formula_note": "mL = tbsp x 14.7868",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ustsp-ml",
      "category": "Volume",
      "from_unit": "US teaspoon",
      "to_unit": "millilitre (mL)",
      "factor": "4.92892",
      "formula_note": "mL = tsp x 4.92892",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-cuft-l",
      "category": "Volume",
      "from_unit": "cubic foot (cu ft)",
      "to_unit": "litre (L)",
      "factor": "28.3168",
      "formula_note": "L = cu ft x 28.3168",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-cuin-ml",
      "category": "Volume",
      "from_unit": "cubic inch (cu in)",
      "to_unit": "millilitre (mL)",
      "factor": "16.3871",
      "formula_note": "mL = cu in x 16.3871",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-usbarrel-l",
      "category": "Volume",
      "from_unit": "US barrel (oil)",
      "to_unit": "litre (L)",
      "factor": "158.987",
      "formula_note": "1 US barrel = 42 US gal (exact)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-uspt-ml",
      "category": "Volume",
      "from_unit": "US pint",
      "to_unit": "millilitre (mL)",
      "factor": "473.176",
      "formula_note": "mL = pt x 473.176",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-ukpt-ml",
      "category": "Volume",
      "from_unit": "UK pint",
      "to_unit": "millilitre (mL)",
      "factor": "568.261",
      "formula_note": "mL = pt x 568.261",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "vol-usqt-l",
      "category": "Volume",
      "from_unit": "US quart",
      "to_unit": "litre (L)",
      "factor": "0.946353",
      "formula_note": "L = qt x 0.946353",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-m2-sqft",
      "category": "Area",
      "from_unit": "square metre (m^2)",
      "to_unit": "square foot (sq ft)",
      "factor": "10.7639",
      "formula_note": "sq ft = m^2 x 10.7639",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-m2-sqin",
      "category": "Area",
      "from_unit": "square metre (m^2)",
      "to_unit": "square inch (sq in)",
      "factor": "1550",
      "formula_note": "sq in = m^2 x 1550.0031",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-sqft-m2",
      "category": "Area",
      "from_unit": "square foot (sq ft)",
      "to_unit": "square metre (m^2)",
      "factor": "0.092903",
      "formula_note": "m^2 = sq ft x 0.09290304 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-sqft-sqin",
      "category": "Area",
      "from_unit": "square foot (sq ft)",
      "to_unit": "square inch (sq in)",
      "factor": "144",
      "formula_note": "1 sq ft = 144 sq in by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-sqin-cm2",
      "category": "Area",
      "from_unit": "square inch (sq in)",
      "to_unit": "square centimetre (cm^2)",
      "factor": "6.4516",
      "formula_note": "cm^2 = sq in x 6.4516 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-acre-m2",
      "category": "Area",
      "from_unit": "acre",
      "to_unit": "square metre (m^2)",
      "factor": "4046.86",
      "formula_note": "1 acre = 43560 sq ft (exact)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-acre-ha",
      "category": "Area",
      "from_unit": "acre",
      "to_unit": "hectare (ha)",
      "factor": "0.404686",
      "formula_note": "ha = acre x 0.40468564224 (exact)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-acre-sqft",
      "category": "Area",
      "from_unit": "acre",
      "to_unit": "square foot (sq ft)",
      "factor": "43560",
      "formula_note": "1 acre = 43560 sq ft by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-ha-m2",
      "category": "Area",
      "from_unit": "hectare (ha)",
      "to_unit": "square metre (m^2)",
      "factor": "10000",
      "formula_note": "m^2 = ha x 10000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-ha-acre",
      "category": "Area",
      "from_unit": "hectare (ha)",
      "to_unit": "acre",
      "factor": "2.47105",
      "formula_note": "acre = ha x 2.47105",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-km2-m2",
      "category": "Area",
      "from_unit": "square kilometre (km^2)",
      "to_unit": "square metre (m^2)",
      "factor": "1000000",
      "formula_note": "m^2 = km^2 x 1000000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-km2-sqmi",
      "category": "Area",
      "from_unit": "square kilometre (km^2)",
      "to_unit": "square mile (sq mi)",
      "factor": "0.386102",
      "formula_note": "sq mi = km^2 x 0.386102",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-sqmi-km2",
      "category": "Area",
      "from_unit": "square mile (sq mi)",
      "to_unit": "square kilometre (km^2)",
      "factor": "2.58999",
      "formula_note": "km^2 = sq mi x 2.589988110336",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-sqmi-acre",
      "category": "Area",
      "from_unit": "square mile (sq mi)",
      "to_unit": "acre",
      "factor": "640",
      "formula_note": "1 sq mi = 640 acres by definition",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-marla-m2",
      "category": "Area",
      "from_unit": "marla (Pakistan)",
      "to_unit": "square metre (m^2)",
      "factor": "25.2929",
      "formula_note": "1 marla = 272.25 sq ft (Pakistan)",
      "is_exact": false,
      "source_name": "Pakistan land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-marla-sqft",
      "category": "Area",
      "from_unit": "marla (Pakistan)",
      "to_unit": "square foot (sq ft)",
      "factor": "272.25",
      "formula_note": "1 marla = 272.25 sq ft (Pakistan standard)",
      "is_exact": true,
      "source_name": "Pakistan land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-kanal-m2",
      "category": "Area",
      "from_unit": "kanal (Pakistan)",
      "to_unit": "square metre (m^2)",
      "factor": "505.857",
      "formula_note": "1 kanal = 20 marla (Pakistan)",
      "is_exact": false,
      "source_name": "Pakistan land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-bigha-m2",
      "category": "Area",
      "from_unit": "bigha (Uttar Pradesh)",
      "to_unit": "square metre (m^2)",
      "factor": "2529.29",
      "formula_note": "1 bigha = 100 marla (varies by state in India)",
      "is_exact": false,
      "source_name": "Indian land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "area-cent-m2",
      "category": "Area",
      "from_unit": "cent (South India)",
      "to_unit": "square metre (m^2)",
      "factor": "40.4686",
      "formula_note": "1 cent = 1/100 acre",
      "is_exact": false,
      "source_name": "South Indian land measurement standard",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-c-f",
      "category": "Temperature",
      "from_unit": "Celsius (C)",
      "to_unit": "Fahrenheit (F)",
      "factor": "formula",
      "formula_note": "F = C x 9/5 + 32 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-f-c",
      "category": "Temperature",
      "from_unit": "Fahrenheit (F)",
      "to_unit": "Celsius (C)",
      "factor": "formula",
      "formula_note": "C = (F - 32) x 5/9 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-c-k",
      "category": "Temperature",
      "from_unit": "Celsius (C)",
      "to_unit": "kelvin (K)",
      "factor": "formula",
      "formula_note": "K = C + 273.15 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-k-c",
      "category": "Temperature",
      "from_unit": "kelvin (K)",
      "to_unit": "Celsius (C)",
      "factor": "formula",
      "formula_note": "C = K - 273.15 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-f-r",
      "category": "Temperature",
      "from_unit": "Fahrenheit (F)",
      "to_unit": "Rankine (R)",
      "factor": "formula",
      "formula_note": "R = F + 459.67 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-c-r",
      "category": "Temperature",
      "from_unit": "Celsius (C)",
      "to_unit": "Rankine (R)",
      "factor": "formula",
      "formula_note": "R = (C + 273.15) x 9/5 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "temp-k-r",
      "category": "Temperature",
      "from_unit": "kelvin (K)",
      "to_unit": "Rankine (R)",
      "factor": "formula",
      "formula_note": "R = K x 9/5 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mps-kmh",
      "category": "Speed and velocity",
      "from_unit": "metre per second (m/s)",
      "to_unit": "kilometre per hour (km/h)",
      "factor": "3.6",
      "formula_note": "km/h = m/s x 3.6 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mps-mph",
      "category": "Speed and velocity",
      "from_unit": "metre per second (m/s)",
      "to_unit": "mile per hour (mph)",
      "factor": "2.23694",
      "formula_note": "mph = m/s / 0.44704",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mps-fts",
      "category": "Speed and velocity",
      "from_unit": "metre per second (m/s)",
      "to_unit": "foot per second (ft/s)",
      "factor": "3.28084",
      "formula_note": "ft/s = m/s / 0.3048",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mps-knots",
      "category": "Speed and velocity",
      "from_unit": "metre per second (m/s)",
      "to_unit": "knot (kn)",
      "factor": "1.94384",
      "formula_note": "kn = m/s x 3600 / 1852",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-kmh-mph",
      "category": "Speed and velocity",
      "from_unit": "kilometre per hour (km/h)",
      "to_unit": "mile per hour (mph)",
      "factor": "0.621371",
      "formula_note": "mph = km/h / 1.609344",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-kmh-mps",
      "category": "Speed and velocity",
      "from_unit": "kilometre per hour (km/h)",
      "to_unit": "metre per second (m/s)",
      "factor": "0.277778",
      "formula_note": "m/s = km/h / 3.6",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mph-kmh",
      "category": "Speed and velocity",
      "from_unit": "mile per hour (mph)",
      "to_unit": "kilometre per hour (km/h)",
      "factor": "1.609344",
      "formula_note": "km/h = mph x 1.609344 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mph-mps",
      "category": "Speed and velocity",
      "from_unit": "mile per hour (mph)",
      "to_unit": "metre per second (m/s)",
      "factor": "0.44704",
      "formula_note": "m/s = mph x 0.44704 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-knot-kmh",
      "category": "Speed and velocity",
      "from_unit": "knot (kn)",
      "to_unit": "kilometre per hour (km/h)",
      "factor": "1.852",
      "formula_note": "km/h = kn x 1.852 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-knot-mph",
      "category": "Speed and velocity",
      "from_unit": "knot (kn)",
      "to_unit": "mile per hour (mph)",
      "factor": "1.15078",
      "formula_note": "mph = kn x 1852/1609.344",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-fts-mps",
      "category": "Speed and velocity",
      "from_unit": "foot per second (ft/s)",
      "to_unit": "metre per second (m/s)",
      "factor": "0.3048",
      "formula_note": "m/s = ft/s x 0.3048 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "speed-mach-mps",
      "category": "Speed and velocity",
      "from_unit": "Mach (sea level 15 C)",
      "to_unit": "metre per second (m/s)",
      "factor": "340.29",
      "formula_note": "standard atmosphere speed of sound",
      "is_exact": false,
      "source_name": "ISO 2533 standard atmosphere",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-j-cal",
      "category": "Energy",
      "from_unit": "joule (J)",
      "to_unit": "calorie (cal, thermochem)",
      "factor": "0.239006",
      "formula_note": "cal = J / 4.184 (thermochem)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-j-wh",
      "category": "Energy",
      "from_unit": "joule (J)",
      "to_unit": "watt-hour (Wh)",
      "factor": "0.000277778",
      "formula_note": "Wh = J / 3600 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-cal-j",
      "category": "Energy",
      "from_unit": "calorie (cal, thermochem)",
      "to_unit": "joule (J)",
      "factor": "4.184",
      "formula_note": "J = cal x 4.184 (thermochem, exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-kcal-j",
      "category": "Energy",
      "from_unit": "kilocalorie (kcal)",
      "to_unit": "joule (J)",
      "factor": "4184",
      "formula_note": "J = kcal x 4184 (thermochem, exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-wh-j",
      "category": "Energy",
      "from_unit": "watt-hour (Wh)",
      "to_unit": "joule (J)",
      "factor": "3600",
      "formula_note": "J = Wh x 3600 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-kwh-j",
      "category": "Energy",
      "from_unit": "kilowatt-hour (kWh)",
      "to_unit": "joule (J)",
      "factor": "3600000",
      "formula_note": "J = kWh x 3600000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-kwh-btu",
      "category": "Energy",
      "from_unit": "kilowatt-hour (kWh)",
      "to_unit": "BTU (international table)",
      "factor": "3412.14",
      "formula_note": "BTU = kWh x 3412.14",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-btu-j",
      "category": "Energy",
      "from_unit": "BTU (international table)",
      "to_unit": "joule (J)",
      "factor": "1055.06",
      "formula_note": "J = BTU x 1055.05585262 (IT)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-ev-j",
      "category": "Energy",
      "from_unit": "electronvolt (eV)",
      "to_unit": "joule (J)",
      "factor": "1.602176634e-19",
      "formula_note": "J = eV x 1.602176634e-19 (exact, SI 2019)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-erg-j",
      "category": "Energy",
      "from_unit": "erg",
      "to_unit": "joule (J)",
      "factor": "1e-7",
      "formula_note": "J = erg x 1e-7 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-therm-j",
      "category": "Energy",
      "from_unit": "therm (US)",
      "to_unit": "joule (J)",
      "factor": "1.05506e8",
      "formula_note": "J = therm x 1.05506e8 (approx)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "energy-ftlb-j",
      "category": "Energy",
      "from_unit": "foot-pound (ft-lb)",
      "to_unit": "joule (J)",
      "factor": "1.35582",
      "formula_note": "J = ft-lb x 1.355817948",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-w-hp",
      "category": "Power",
      "from_unit": "watt (W)",
      "to_unit": "horsepower (mechanical)",
      "factor": "0.00134102",
      "formula_note": "hp = W / 745.6998715822702",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-hp-w",
      "category": "Power",
      "from_unit": "horsepower (mechanical)",
      "to_unit": "watt (W)",
      "factor": "745.7",
      "formula_note": "W = hp x 745.6998715822702",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-hp-metric-w",
      "category": "Power",
      "from_unit": "horsepower (metric / PS)",
      "to_unit": "watt (W)",
      "factor": "735.499",
      "formula_note": "W = PS x 735.49875",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-btuh-w",
      "category": "Power",
      "from_unit": "BTU per hour (BTU/h)",
      "to_unit": "watt (W)",
      "factor": "0.293071",
      "formula_note": "W = BTU/h x 0.29307107",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-tonref-w",
      "category": "Power",
      "from_unit": "ton of refrigeration",
      "to_unit": "watt (W)",
      "factor": "3516.85",
      "formula_note": "W = ton x 3516.85284 (12000 BTU/h IT)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-kw-w",
      "category": "Power",
      "from_unit": "kilowatt (kW)",
      "to_unit": "watt (W)",
      "factor": "1000",
      "formula_note": "W = kW x 1000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-kw-hp",
      "category": "Power",
      "from_unit": "kilowatt (kW)",
      "to_unit": "horsepower (mechanical)",
      "factor": "1.34102",
      "formula_note": "hp = kW x 1000 / 745.6998715822702",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-mw-w",
      "category": "Power",
      "from_unit": "megawatt (MW)",
      "to_unit": "watt (W)",
      "factor": "1000000",
      "formula_note": "W = MW x 1000000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "power-ergs-w",
      "category": "Power",
      "from_unit": "erg per second",
      "to_unit": "watt (W)",
      "factor": "1e-7",
      "formula_note": "W = erg/s x 1e-7 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-atm-pa",
      "category": "Pressure",
      "from_unit": "atmosphere (atm)",
      "to_unit": "pascal (Pa)",
      "factor": "101325",
      "formula_note": "Pa = atm x 101325 (exact, standard)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-atm-bar",
      "category": "Pressure",
      "from_unit": "atmosphere (atm)",
      "to_unit": "bar",
      "factor": "1.01325",
      "formula_note": "bar = atm x 1.01325",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-atm-mmhg",
      "category": "Pressure",
      "from_unit": "atmosphere (atm)",
      "to_unit": "millimetre of mercury (mmHg)",
      "factor": "760",
      "formula_note": "mmHg = atm x 760 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-atm-psi",
      "category": "Pressure",
      "from_unit": "atmosphere (atm)",
      "to_unit": "pound per square inch (psi)",
      "factor": "14.6959",
      "formula_note": "psi = atm x 14.69594878",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-atm-inhg",
      "category": "Pressure",
      "from_unit": "atmosphere (atm)",
      "to_unit": "inch of mercury (inHg)",
      "factor": "29.9213",
      "formula_note": "inHg = atm x 29.9213",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-bar-pa",
      "category": "Pressure",
      "from_unit": "bar",
      "to_unit": "pascal (Pa)",
      "factor": "100000",
      "formula_note": "Pa = bar x 100000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-psi-pa",
      "category": "Pressure",
      "from_unit": "pound per square inch (psi)",
      "to_unit": "pascal (Pa)",
      "factor": "6894.76",
      "formula_note": "Pa = psi x 6894.757293168",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-mmhg-pa",
      "category": "Pressure",
      "from_unit": "millimetre of mercury (mmHg)",
      "to_unit": "pascal (Pa)",
      "factor": "133.322",
      "formula_note": "Pa = mmHg x 133.322387415",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-inhg-pa",
      "category": "Pressure",
      "from_unit": "inch of mercury (inHg)",
      "to_unit": "pascal (Pa)",
      "factor": "3386.39",
      "formula_note": "Pa = inHg x 3386.388640341",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-torr-pa",
      "category": "Pressure",
      "from_unit": "torr (Torr)",
      "to_unit": "pascal (Pa)",
      "factor": "133.322",
      "formula_note": "Pa = Torr x 101325/760",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-kpa-pa",
      "category": "Pressure",
      "from_unit": "kilopascal (kPa)",
      "to_unit": "pascal (Pa)",
      "factor": "1000",
      "formula_note": "Pa = kPa x 1000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-kpa-psi",
      "category": "Pressure",
      "from_unit": "kilopascal (kPa)",
      "to_unit": "pound per square inch (psi)",
      "factor": "0.145038",
      "formula_note": "psi = kPa x 0.145038",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-mpa-pa",
      "category": "Pressure",
      "from_unit": "megapascal (MPa)",
      "to_unit": "pascal (Pa)",
      "factor": "1000000",
      "formula_note": "Pa = MPa x 1000000 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "pressure-mbar-pa",
      "category": "Pressure",
      "from_unit": "millibar (mbar)",
      "to_unit": "pascal (Pa)",
      "factor": "100",
      "formula_note": "Pa = mbar x 100 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-min-s",
      "category": "Time",
      "from_unit": "minute (min)",
      "to_unit": "second (s)",
      "factor": "60",
      "formula_note": "s = min x 60 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-h-s",
      "category": "Time",
      "from_unit": "hour (h)",
      "to_unit": "second (s)",
      "factor": "3600",
      "formula_note": "s = h x 3600 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-h-min",
      "category": "Time",
      "from_unit": "hour (h)",
      "to_unit": "minute (min)",
      "factor": "60",
      "formula_note": "min = h x 60 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-d-s",
      "category": "Time",
      "from_unit": "day (d)",
      "to_unit": "second (s)",
      "factor": "86400",
      "formula_note": "s = d x 86400 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-d-h",
      "category": "Time",
      "from_unit": "day (d)",
      "to_unit": "hour (h)",
      "factor": "24",
      "formula_note": "h = d x 24 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-week-s",
      "category": "Time",
      "from_unit": "week",
      "to_unit": "second (s)",
      "factor": "604800",
      "formula_note": "s = week x 604800 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-week-d",
      "category": "Time",
      "from_unit": "week",
      "to_unit": "day (d)",
      "factor": "7",
      "formula_note": "d = week x 7 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-fortnight-d",
      "category": "Time",
      "from_unit": "fortnight",
      "to_unit": "day (d)",
      "factor": "14",
      "formula_note": "d = fortnight x 14 (exact)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-year-julian-s",
      "category": "Time",
      "from_unit": "year (Julian)",
      "to_unit": "second (s)",
      "factor": "31557600",
      "formula_note": "s = year x 31557600 (exact, 365.25 d)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-year-greg-s",
      "category": "Time",
      "from_unit": "year (Gregorian)",
      "to_unit": "second (s)",
      "factor": "31556952",
      "formula_note": "s = year x 31556952 (365.2425 d)",
      "is_exact": true,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-month-avg-d",
      "category": "Time",
      "from_unit": "month (average Gregorian)",
      "to_unit": "day (d)",
      "factor": "30.4369",
      "formula_note": "year / 12 = 30.4369 d (Gregorian average)",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-sidereal-d-s",
      "category": "Time",
      "from_unit": "sidereal day",
      "to_unit": "second (s)",
      "factor": "86164.0905",
      "formula_note": "s = sidereal day x 86164.0905",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "time-lunar-month-s",
      "category": "Time",
      "from_unit": "lunar month (synodic)",
      "to_unit": "second (s)",
      "factor": "2551442.9",
      "formula_note": "mean synodic month = 29.530589 d",
      "is_exact": false,
      "source_name": "NIST",
      "source_url": "https://physics.nist.gov/cuu/Units/",
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-byte-bits",
      "category": "Data storage",
      "from_unit": "byte (B)",
      "to_unit": "bit",
      "factor": "8",
      "formula_note": "bit = B x 8 (exact)",
      "is_exact": true,
      "source_name": "IEEE 1541",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-nibble-bits",
      "category": "Data storage",
      "from_unit": "nibble",
      "to_unit": "bit",
      "factor": "4",
      "formula_note": "bit = nibble x 4 (exact)",
      "is_exact": true,
      "source_name": "IEEE 1541",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-kib-b",
      "category": "Data storage",
      "from_unit": "kibibyte (KiB)",
      "to_unit": "byte (B)",
      "factor": "1024",
      "formula_note": "B = KiB x 1024 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-kb-b-dec",
      "category": "Data storage",
      "from_unit": "kilobyte (KB, decimal)",
      "to_unit": "byte (B)",
      "factor": "1000",
      "formula_note": "B = KB x 1000 (decimal, SI)",
      "is_exact": true,
      "source_name": "SI / IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-mib-b",
      "category": "Data storage",
      "from_unit": "mebibyte (MiB)",
      "to_unit": "byte (B)",
      "factor": "1048576",
      "formula_note": "B = MiB x 1048576 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-mb-b-dec",
      "category": "Data storage",
      "from_unit": "megabyte (MB, decimal)",
      "to_unit": "byte (B)",
      "factor": "1000000",
      "formula_note": "B = MB x 1000000 (decimal, SI)",
      "is_exact": true,
      "source_name": "SI / IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-gib-b",
      "category": "Data storage",
      "from_unit": "gibibyte (GiB)",
      "to_unit": "byte (B)",
      "factor": "1073741824",
      "formula_note": "B = GiB x 1073741824 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-gb-b-dec",
      "category": "Data storage",
      "from_unit": "gigabyte (GB, decimal)",
      "to_unit": "byte (B)",
      "factor": "1000000000",
      "formula_note": "B = GB x 1000000000 (decimal, SI)",
      "is_exact": true,
      "source_name": "SI / IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-tib-b",
      "category": "Data storage",
      "from_unit": "tebibyte (TiB)",
      "to_unit": "byte (B)",
      "factor": "1099511627776",
      "formula_note": "B = TiB x 1099511627776 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-tb-b-dec",
      "category": "Data storage",
      "from_unit": "terabyte (TB, decimal)",
      "to_unit": "byte (B)",
      "factor": "1000000000000",
      "formula_note": "B = TB x 1000000000000 (decimal, SI)",
      "is_exact": true,
      "source_name": "SI / IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-pib-b",
      "category": "Data storage",
      "from_unit": "pebibyte (PiB)",
      "to_unit": "byte (B)",
      "factor": "1125899906842624",
      "formula_note": "B = PiB x 1125899906842624 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    },
    {
      "id": "data-eib-b",
      "category": "Data storage",
      "from_unit": "exbibyte (EiB)",
      "to_unit": "byte (B)",
      "factor": "1152921504606846976",
      "formula_note": "B = EiB x 1152921504606846976 (exact, IEC binary)",
      "is_exact": true,
      "source_name": "IEC 80000-13",
      "source_url": null,
      "last_verified": "2026-06-03"
    }
  ]
}