Pressure Converter: PSI, Bar, Pa, atm, Torr
Convert between every pressure unit in one tool. Pascal (Pa), kilopascal (kPa), bar, PSI, atmosphere, Torr (mmHg), inch of mercury (inHg), and millibar. Useful for tire inflation, blood pressure conversion, weather reports, engineering, scuba diving, and laboratory work. Any-to-any conversion with one tap to swap direction.
Pressure unit converter
1 PSI = 0.0689476 Bar
Common pressure values
Pressures you meet in everyday life with their equivalents.
| Use case | PSI | kPa | Bar |
|---|---|---|---|
| Car tire (normal) | 32 PSI | 221 kPa | 2.21 bar |
| Bicycle road tire | 90 PSI | 621 kPa | 6.21 bar |
| Atmospheric (sea level) | 14.7 PSI | 101.3 kPa | 1.01 bar |
| Blood pressure (systolic) | 2.3 PSI | 16 kPa | 0.16 bar |
| Compressed air (shop) | 120 PSI | 827 kPa | 8.27 bar |
| Steam boiler (residential) | 15 PSI | 103 kPa | 1.03 bar |
| Hydraulic system (typical) | 3,000 PSI | 20,684 kPa | 207 bar |
| Diving (10m depth) | 29.4 PSI | 203 kPa | 2.03 bar |
About pressure
What is pressure?
Pressure is force per unit area, measured in Pascals (Pa) in the SI system. One Pascal equals one Newton spread over one square meter. The Pascal is a very small unit; everyday pressures are typically expressed in kilopascals (kPa), bars, PSI, or atmospheres. Pressure is what makes tires hold up cars, what drives fluid through pipes, and what determines how deep a submarine can go.
Atmospheric pressure
The weight of the air column above us creates roughly 101.325 kPa (14.7 PSI, 1.013 bar, 1 atm, 760 mmHg) at sea level. Pressure decreases with altitude: at 5,000 m it drops to about 54 kPa, at the top of Everest (8,848 m) to about 33 kPa. This is why airliners pressurize cabins and high-altitude hikers need acclimatization.
Tire pressure
Most car tires are inflated to 30 to 35 PSI (207 to 241 kPa, 2.07 to 2.41 bar). The correct pressure is on the placard inside your driver-side door. Higher pressure (within safe limits) reduces rolling resistance and improves fuel economy by 1 to 3 percent. Lower pressure improves grip on rough roads but wears tires faster. Always check tire pressure when cold; pressure rises 1 PSI per 10 degrees Fahrenheit warming.
Blood pressure
Blood pressure is measured in millimeters of mercury (mmHg, also called Torr). The first number (systolic) is the peak pressure when the heart contracts; the second (diastolic) is the minimum between beats. Normal: about 120/80 mmHg. Hypertension typically starts at 130/80 or 140/90 depending on guidelines. The calculator converts mmHg to other units for academic interest, but medical use sticks to mmHg.
Weather pressure
Atmospheric pressure variations drive weather. Reported in hectopascals (hPa) or millibars (mbar), numerically the same. Sea-level average is 1013 hPa. High pressure (above 1020 hPa) brings clear stable weather; low pressure (below 1000 hPa) brings storms. A sharp drop of 10+ hPa over a few hours often signals an approaching storm. Hurricanes can have central pressures below 920 hPa.
PSI in industrial use
Most industrial pressures in the US are quoted in PSI: workshop compressed air at 90-120 PSI, hydraulic systems at 2,000-5,000 PSI, fire hoses at 100-200 PSI. Outside the US, bar is more common: 6 to 10 bar for shop air, 200-350 bar for hydraulics. The calculator translates between any of these.
Gauge vs absolute pressure
Gauge pressure is measured relative to local atmospheric pressure (so 0 gauge = atmospheric). Tire gauges, blood pressure cuffs, and most consumer-facing measurements show gauge pressure. Absolute pressure includes the surrounding atmosphere (so absolute = gauge + atmospheric). Scientific work typically uses absolute pressure. The calculator converts between units; the gauge vs absolute distinction is independent of unit choice.
Pressure underwater
Water adds about 1 atm (14.7 PSI, 101 kPa) per 10 meters of depth. So at 30 m depth a diver experiences 4 atm absolute (1 atm from atmosphere + 3 atm from water). This is why scuba tanks fill at 200-300 bar to provide enough air at depth, and why divers must ascend slowly to let dissolved nitrogen come out of solution safely.
Pressure in engineering
Pipe networks, boilers, pneumatic actuators, and hydraulic presses all rely on careful pressure design. The yield strength of common pipe materials is hundreds of MPa (Megapascals). 1 MPa = 1000 kPa = 145 PSI. The calculator handles values across many orders of magnitude, useful in both small (vacuum chambers at micropascals) and large (deep-sea pressures at MPa) contexts.
Divide PSI by 14.5038 to get bar. So 30 PSI = 2.07 bar. Multiply bar by 14.5038 to go the other way: 2 bar = 29.0 PSI. The calculator handles this in one tap.
1 atmosphere (atm) = 14.696 PSI = 1.01325 bar = 101,325 Pascals. This is the standard sea-level air pressure at 15 degrees Celsius. Tire pressures, blood pressure, and weather pressure are all related to this baseline.
It varies by vehicle. Typical car tire pressures are 30 to 35 PSI (2.1 to 2.4 bar). Check the placard inside your driver-side door or in the owner's manual for the correct figure. Trucks and SUVs are often 35 to 45 PSI. Bicycles range from 40 PSI (mountain) to 100+ PSI (road).
In millimeters of mercury (mmHg, also called Torr). A normal blood pressure is around 120/80 mmHg. The calculator converts mmHg to other pressure units: 120 mmHg = 16 kPa = 2.32 PSI. Medical use, however, always sticks to mmHg.
Pascal (Pa), Kilopascal (kPa), Bar, PSI, Atmosphere (atm), Torr / mmHg, Inch of Mercury (inHg), and Millibar (mbar). Any-to-any conversion is supported.
Pascal (Pa), defined as 1 Newton of force per square meter. The Pascal is a small unit; 1 Pa is roughly the pressure of a piece of paper resting flat on a table. Practical pressures are usually quoted in kilopascals (kPa) or megapascals (MPa). 1 atm = 101,325 Pa = 101.325 kPa.
PSI is the legacy US unit and is still used for tires in the US, UK, and several other countries. Most of the world uses kPa or bar. Modern tire labels and vehicle placards often list both. The calculator lets you convert any pressure unit to any other for inflation reference.
Weather forecasts use hectopascals (hPa) or millibars (mbar), which are numerically identical (1 hPa = 1 mbar). Sea-level pressure averages 1013 hPa. A "high pressure" weather system is above 1020 hPa; a "low" is below 1000 hPa. In inches of mercury, sea-level pressure averages 29.92 inHg.
Gauge pressure is measured relative to ambient atmospheric pressure (so 0 gauge = atmospheric pressure). Absolute pressure includes the surrounding atmosphere. Tire gauges, blood pressure cuffs, and most everyday measurements show gauge pressure. Scientific measurements often use absolute. The calculator handles both as a single number; you choose the reference frame.
Water adds about 1 atm (14.7 PSI / 101 kPa) per 10 meters of depth. So at the bottom of a 3-meter deep pool, you experience about 1.3 atm absolute (or 0.3 atm gauge, since the water surface is at 1 atm). At 10 meters depth you experience 2 atm absolute (1 atm gauge).
Hydraulic systems often run at 100 to 350 bar (1,500 to 5,000 PSI). Diesel engine fuel injection: 1,500 to 2,500 bar. Boiler steam: 10 to 200 bar. Compressed air systems: 6 to 10 bar. The calculator handles any pressure level relevant for engineering work.
The conversion factors are exact, taken from international standards. Results are shown to 6 significant figures. For research-grade measurement, double-check against the original units published in your reference; the calculator uses standard SI-defined conversion factors.
Yes. All values stay in your browser. Nothing is sent to a server, logged, or shared. You can use the calculator offline once the page has loaded.