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Free Online Calculators
for Money, Time, Health & School

From loan and tax calculators to age, BMI, GPA, payroll, and date tools - find the right calculator in a few clicks.

Popular:MortgageBMIPercentagePaycheck
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Three steps to the answer you need.

Step 1

Search

Type a keyword like "mortgage" or "age" to find the right tool instantly.

Step 2

Pick

Choose from our curated list of 73+ free, accurate calculators.

Step 3

Calculate

Enter your values and get instant, reliable results — no signup needed.

Explore Calculator Categories

6 specialized categories with 73+ free calculators

Finance

Mortgage, loans, investments, savings, and retirement planning tools.

12 calculators

Paycheck

Salary, take-home pay, taxes, and payroll calculation tools.

8 calculators

Health

BMI, calories, body fat, fitness, and wellness calculators.

15 calculators

Education

Grade, GPA, final exam, and academic performance calculators.

8 calculators

Math

Percentage, fractions, algebra, geometry, and unit conversion tools.

24 calculators

Date & Time

Age, date differences, time zones, and birthday calculation tools.

6 calculators

Hot Calculators Right Now

Most-used tools this month

Finance

Mortgage Calculator

Calculate your monthly mortgage payment, total interest, and amortization schedule.

Health

BMI Calculator

Calculate your Body Mass Index and interpret your weight category.

Paycheck

Paycheck Calculator

Estimate your take-home pay after federal, state, and local taxes.

Math

Percentage Calculator

Calculate percentages, percent change, and percent of a number.

Education

Grade Calculator

Calculate your weighted course grade from assignment scores.

Date & Time

Age Calculator

Calculate exact age in years, months, and days from any birthdate.

Health

Calorie Calculator

Find out how many calories you need daily to reach your goals.

Finance

Compound Interest Calculator

See how your investments grow with the power of compound interest.

Developer API

Integrate Our Calculator API

Embed any of our 73+ calculators into your app or website. Simple REST API with instant results, real-time data, and JSON responses.

Get API Access
mortgage.js
fetch('https://api.calculators.run/v1/mortgage', {
  method: 'POST',
  headers: { 'Authorization': 'Bearer YOUR_KEY' },
  body: JSON.stringify({
    principal: 400000,
    rate: 6.5,
    term: 30
  })
})
// → { monthly: 2528.27, total: 910174.2 }

Testimonials

What our customers are saying

Jonathan Yombo

Software Engineer

Calculators.RUN is really extraordinary and very practical. I got my mortgage calculation done in seconds — a real time saver.

Yves Kalume

GDE - Android

I use Calculators.RUN for my paycheck calculations every week. It's so clean and fast — I've recommended it to my whole team.

Yucel Faruksahan

Tailkits Creator

Great work on Calculators.RUN. The BMI and calorie calculators are the best I've found on the web so far :)

Anonymous author

Product Manager

I use the grade calculator on Calculators.RUN to track my GPA — it's very clear and easy to use, just enter your grades and you're done.

Shekinah Tshiokufila

Senior Software Engineer

Calculators.RUN is redefining the standard for online calculators — clean design, instant results, and no annoying popups or ads.

Oketa Fred

Fullstack Developer

I absolutely love Calculators.RUN! Every calculator is beautifully designed and easy to use, which makes getting results a total breeze.

Zeki

Founder of ChatExtend

Calculators.RUN is the perfect fusion of simplicity and accuracy. The loan and mortgage calculators have been invaluable for our financial planning.

Joseph Kitheka

Fullstack Developer

Calculators.RUN has transformed how I handle everyday calculations. The wide variety of tools — from finance to health — covers everything I need.

Khatab Wedaa

MerakiUI Creator

Calculators.RUN is elegant, clean, and lightning fast. The date and time calculators are particularly helpful for project planning.

Rodrigo Aguilar

TailwindAwesome Creator

I love Calculators.RUN ❤️. Every tool is well-structured, simple to use, and gives accurate results instantly. My go-to for any calculation.

Eric Ampire

@GoogleDevExpert for Android

Calculators.RUN is the perfect solution for anyone who needs quick, reliable calculations without hunting through complex spreadsheets.

Roland Tubonge

Software Engineer

Calculators.RUN is so well designed that even complex financial calculations become simple. The results are clear and easy to understand.

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