Free Online Calculators - All-in-One Calculator Hub for Finance, Health & Math
30 free online calculators in one place for finance, health and fitness, education, and everyday math. Plan loans, EMIs and mortgages, check your BMI and calorie needs, work out GPA and percentages, and estimate Pakistan salary tax or Zakat. No signup, no download, instant results, and every calculation runs right in your browser.
Gizmoop's free online calculators are a set of 30 browser-based tools spanning four areas: finance (loan, EMI, mortgage, compound interest, SIP, salary), health and fitness (BMI, calorie, body fat, ideal weight, due date, ovulation, sleep), education (GPA, CGPA, matric marks, grade, words to pages), and everyday math (percentage, tip, discount, age, date, time, scientific, electricity bill). They also include localised Pakistan tools like FBR salary tax and Zakat. Every calculator is free with no signup, gives instant results, and runs entirely in your browser so your numbers stay private.
All 30 calculators tools
Everyday calculators for math you do not want to set up a spreadsheet for. Find your exact age, work out percentages and BMI, plan loan, EMI and mortgage repayments, project compound interest and SIP growth, estimate Pakistan salary tax, calculate Zakat, value gold by karat, plus 18 new health, education, and general calculators.
Most popular calculators
The tools in this category people reach for most often.
What is an online calculator hub?
An online calculator hub is a single page that collects many free calculators in one place so you do not have to set up a spreadsheet or hunt for a separate site every time you need a quick number. Gizmoop gathers 30 calculators here, grouped into finance, health and fitness, education, and everyday math, plus a set of localised tools for Pakistan and South Asia.
Each tool answers one job cleanly: type your inputs, read the result, and move on. There is no account to create, nothing to download, and no daily limit. The calculations run in your browser, which keeps them fast and means the numbers you enter are not sent to or stored on a server.
Financial calculators: loans, EMIs and mortgages
The financial calculators are the highest-value tools on the hub because the numbers they produce shape real money decisions. The loan calculator and the EMI calculator both take a principal amount, an interest rate, and a tenure, then return your monthly payment, the total interest you will pay, and a month-by-month amortization schedule so you can see how each instalment splits between principal and interest.
For homebuyers, the mortgage calculator goes a step further by layering property tax, insurance, and PMI on top of the base payment, giving you a realistic monthly figure rather than just principal and interest. Use these together before you sign anything: compare two loan offers, test a shorter tenure, or check how a bigger down payment changes the cost over the life of the loan.
Investment calculators: compound interest, SIP and salary
Once a loan is handled, the next financial question is usually growth. The compound interest calculator shows your final balance, total interest earned, and a year-by-year growth table so you can see the difference monthly versus yearly compounding makes over time. The SIP calculator projects how a regular monthly investment grows, which is the standard way to plan mutual-fund contributions.
On the income side, the salary calculator converts pay between hourly, daily, weekly, monthly, and annual figures, which is handy when you are comparing a contract rate against a salaried offer. Together these tools cover the full money picture: what you owe, what you are saving, and what you earn.
Health and fitness calculators: BMI, calorie and body composition
The health calculators turn body measurements into clear, evidence-based metrics. The BMI calculator gives your body mass index with the standard WHO categories in both metric and imperial units. The calorie calculator estimates your BMR and TDEE and then sets daily calorie targets with a balanced macro split, which is the foundation of any weight goal.
For a more detailed read on body composition, the body fat calculator uses the US Navy method to estimate fat percentage, fat mass, and lean mass with an ACE category, while the ideal weight calculator shows a healthy weight range using the Hamwi, Devine, Robinson, Miller, and WHO BMI formulas. Use BMI for a quick screen, then body fat and ideal weight for context, since BMI alone does not distinguish muscle from fat.
Pregnancy and sleep calculators
The due date calculator estimates your delivery date from either the first day of your last menstrual period or a known conception date, and it reports your current gestational age along the way. The standard method counts 280 days, or 40 weeks, from the first day of the last period. The ovulation calculator complements it by predicting your ovulation day, fertile window, and the two most-fertile days.
The sleep calculator rounds out the wellness set by working backwards or forwards through 90-minute sleep cycles, so you can pick a bedtime that lets you wake at the end of a cycle rather than in the middle of one. These tools are estimates to guide planning, not medical advice, so confirm anything important with a clinician.
Education calculators: GPA, CGPA and grades
Students get a dedicated set of calculators built around how grades are actually scored. The GPA calculator computes your grade point average on the 4.0 scale across unlimited courses, and the CGPA calculator rolls multiple semesters into a cumulative figure on the HEC 4.0 scale used across South Asian universities.
The grade calculator handles weighted grades and tells you exactly what score you need on a final exam to reach a target, while the matric marks calculator produces an overall percentage and grade for Pakistani board exams. For essays and assignments, the words to pages calculator converts a word count into a page count, and back again, accounting for font and spacing. Combine GPA, CGPA, and grade tools across a degree to track progress term by term.
Everyday math calculators: percentage, age and date
The everyday tools cover the quick math you do without wanting a calculator app open. The percentage calculator handles percent of a number, percent change, tips, and discounts in one place, and the dedicated tip calculator and discount calculator make restaurant bills and sale prices effortless, including bill splitting and stacked discounts.
The age calculator returns your exact age in years, months, days, weeks, and hours with a next-birthday countdown. The date calculator finds the days between two dates, counts business days, and adds or subtracts intervals from a date. The time calculator and hours calculator add and subtract durations, convert to decimal hours, and total up work hours and pay for a shift or a full week.
Scientific and general-purpose calculators
When the math gets heavier, the scientific calculator handles trigonometry (sin, cos, tan), logarithms (log and ln), exponents, factorials, and the constants pi and e, all in a clean keypad layout that works on phone and desktop. It is the right tool for homework, lab work, or any one-off calculation that the basic phone calculator cannot manage.
These general-purpose tools sit alongside the everyday-math set so you can move from a quick percentage to a full trig expression without leaving the hub. Everything runs locally, so even complex inputs stay on your device.
Calculators for Pakistan and South Asia
This is the section competitors rarely cover well, and it is where Gizmoop adds the most local value. The Pakistan salary calculator applies the current FBR income tax slabs for the 2025-26 tax year and shows your take-home pay, so you can see the tax impact of a raise or a job offer before you accept it. The Zakat calculator works out your annual Zakat at 2.5 percent and checks your assets against the Nisab threshold.
The electricity bill calculator estimates a Pakistani residential bill from your units consumed using editable slab rates, which matters when tariffs change. The gold price calculator values gold by karat and weight with a built-in weight converter, and the matric marks calculator covers Pakistani board exam grading. These localised tools are accurate for the region in a way generic global calculators are not.
How to choose the right calculator
Start from the decision you are making, not the tool name. For borrowing, use the loan or EMI calculator for personal and auto loans and the mortgage calculator for a home, since the mortgage tool adds tax, insurance, and PMI. For saving and investing, use compound interest for a lump sum and SIP for regular monthly contributions.
For health, treat BMI as a quick screen and reach for body fat and ideal weight when you want context that accounts for muscle. For school, GPA covers a single term, CGPA spans a whole degree, and grade tells you what you still need to score. When your money or marks are tied to Pakistan, the FBR salary, Zakat, electricity bill, and matric tools are calibrated for local rules, so prefer them over generic equivalents.
Why use Gizmoop free online calculators
Every calculator here is completely free with no signup, no download, and no daily limit, and there is no Pro tier holding back the useful parts. Results appear instantly as you type, and the tools work on any device, from a phone keypad to a desktop browser.
Privacy is built in: because each calculation runs in your browser, the numbers you enter, whether a salary, a loan balance, or a health measurement, are not uploaded or stored on a server. Many tools also show the formula or method behind the result, so you can trust the output and understand how it was reached rather than taking a black box on faith.
Popular calculators and what they compute
A quick guide to ten of the most-used calculators on the hub, what each one works out, and who it is most useful for.
| Calculator | What it calculates | Who it is for |
|---|---|---|
| Percentage Calculator | Percent of a number, percent change, tips, and discounts | Students, shoppers, and anyone doing quick math |
| BMI Calculator | Body mass index with WHO weight categories | Anyone tracking weight and general health |
| Age Calculator | Exact age in years, months, days, weeks, and hours | Forms, birthdays, and eligibility checks |
| Loan Calculator | Monthly payment, total interest, and amortization schedule | Personal and auto loan borrowers |
| EMI Calculator | Equated monthly installment with a full schedule | Borrowers comparing instalment plans |
| Mortgage Calculator | Home payment with property tax, insurance, and PMI | Homebuyers planning a purchase |
| Compound Interest Calculator | Final balance and year-by-year growth | Savers and long-term investors |
| GPA Calculator | Grade point average on the 4.0 scale | College and university students |
| Pakistan Salary Calculator | FBR income tax and take-home pay | Salaried employees in Pakistan |
| Zakat Calculator | Annual Zakat at 2.5 percent with Nisab check | Muslims calculating obligatory charity |
Frequently asked questions
If you don't find your question here, ask us directly.
Yes. All 30 calculators on Gizmoop are 100 percent free with no signup, no download, and no usage limits. There is no Pro tier or free trial that runs out, every calculator is fully available to every visitor, and there are no page caps or hidden paywalls on any result.
Yes. These calculators use the same formulas as physical and financial calculators, and because they run in software they often work to higher precision than a handheld device. Many tools also show the formula or method behind the result, so you can verify how each number was calculated rather than trusting a black box.
No. There is no registration, no email confirmation, and nothing to install. Every calculator works the moment you open it in any modern browser on a phone, tablet, or computer. You simply enter your numbers and read the result, with no account ever required.
Yes. Every calculation runs entirely in your own browser, so the values you enter, whether a salary, a loan balance, or a health measurement, are not uploaded to or stored on a server. Nothing leaves your device, which keeps sensitive financial and health inputs completely private.
It depends on the task. Use the GPA calculator for a single term and the CGPA calculator across a whole degree, the grade calculator to find the score you need on a final, the percentage calculator for quick math, and the scientific calculator for trigonometry, logarithms, and exponents.
Enter three inputs into the EMI calculator or loan calculator: the principal amount you are borrowing, the annual interest rate, and the tenure in months or years. The tool returns your fixed monthly payment, the total interest over the loan, and a full month-by-month amortization schedule.
The standard method counts 280 days, which is 40 weeks, from the first day of your last menstrual period. The due date calculator does this automatically and can also work from a known conception date, reporting your current gestational age. The ovulation calculator adds your fertile window.
Open the Pakistan salary calculator, enter your gross salary, and select the tax year. The tool applies the current FBR income tax slabs for the 2025-26 tax year and shows your tax owed and your take-home pay, so you can see the net effect of a raise or a new job offer.
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