Free Online Calculators

Free online calculators for math, finance, health and everyday unit conversion, each showing how the result is worked out so you can check the answer instead of taking it on trust.

Online Calculators by Category

Pick a category to find the right online calculator: math, health and fitness, financial, physics, or unit converters and utility tools. Each calculator page shows the formula behind the result, and many include a step-by-step breakdown.

Math icon

Math

Calculators for geometry, averages, multiplication and other core math, with the formula and worked steps shown.
Health icon

Health

Estimates for body mass index, energy needs, body fat and pregnancy dates, based on published formulas.
Financial icon

Financial

Calculators for loan payments, amortization, interest, APY and profit, with the formula shown.
Physics icon

Physics

Calculators for motion, forces, energy, electrical power, waves and material stress, with formulas and units shown.
Specialty icon

Specialty

Unit converters and everyday tools for dates, time zones, grades and percentages, with the conversion factors shown.

Popular Online Calculators

Not sure where to start? These are some of the most used calculators on the site.

BMI CalculatorHealth Percentage CalculatorMath Mortgage Payment CalculatorFinancial Loan CalculatorFinancial Daily Calorie CalculatorHealth Age CalculatorSpecialty Unit ConverterSpecialty Scientific CalculatorMath Total Daily Energy Expenditure CalculatorHealth Salary CalculatorFinancial Fraction CalculatorMath GPA CalculatorSpecialty

About CalcMate Online Calculators

Formulas come from published sources such as WHO, NIST and official government publications, and each calculator page shows when it was last updated. Health and financial results are estimates for general information, not medical or financial advice.

All calculators are free and need no signup. Calculations run in your browser, so the numbers you enter are not sent to our servers or stored.

Questions and Answers

Are the online calculators free, and do they work on phones?

Yes, every calculator is free, needs no registration and works in any modern mobile browser on iOS and Android. You open a page, enter your values and get the result right away, and there is no app to install.

Can I rely on the health and financial calculators for decisions?

Use them for estimates, not final decisions. Health results follow published methods such as the Mifflin-St Jeor equation (1990) for calorie needs and WHO categories (2000) for BMI, and financial results leave out taxes, insurance and fees. They do not replace advice from a doctor or a licensed financial advisor.

Do the calculators show step-by-step solutions?

Most math and physics calculators do. The steps show which formula was used and how each value was put into it, so you can follow the logic or check your homework.

How accurate are the calculators?

Each calculator is built from a published formula or an official source, and I check the output against known examples before it goes live, such as a 3-4-5 right triangle for the hypotenuse or a 30-year, $300,000 loan at 6.5% with a payment of $1,896.20. Every page shows the date it was last updated. If a result looks wrong to you, email [email protected] and I will look into it.

Is the data I enter stored or tracked?

No. Calculations run in your browser, and the numbers you enter are not sent to our servers or stored.

What online calculators can I use on CalcMate?

CalcMate has more than 100 free online calculators for math, finance, health, physics and unit conversion, available in 9 languages. Popular ones include mortgage payments, BMI, percentages, equation solving and salary after tax. Browse by category or use the search box to find a specific tool.