Free Online Calculators for Everyday Life

CalcMate is a growing collection of free, fast, and accurate calculators. Everything runs instantly in your browser — no signup, no data collection.

All Tools

Age Calculator

Calculate your exact age in years, months, and days from your date of birth. Also shows total days lived and a countdown to your next birthday.

Date Difference Calculator

Count the days, weeks, months, and years between any two dates. Perfect for deadlines, anniversaries, project timelines, and countdowns.

Percentage Calculator

Work out percentages instantly: what is X% of Y, X is what percent of Y, and percentage increase or decrease between two numbers.

BMI Calculator

Calculate your Body Mass Index from height and weight in metric or imperial units, see your WHO weight category, and the healthy weight range for your height.

Tip Calculator

Work out the tip and total for any bill, split it between any number of people, and round the total up or down to a clean amount.

Discount Calculator

Find the sale price and money saved from a percentage discount, stack a second discount, and see the effective total percentage off.

Loan Calculator

Calculate the monthly payment, total interest, and total cost of a loan or mortgage from the amount, annual interest rate, and term.

Compound Interest Calculator

See how savings or investments grow over time with compound interest and optional regular contributions, at any compounding frequency.

Calorie Calculator

Estimate your daily calorie needs (TDEE) from age, sex, height, weight, and activity level using the Mifflin-St Jeor equation, with targets for losing or gaining weight.

Sales Tax Calculator

Add sales tax to a price to get the tax amount and total, or work backwards from a tax-inclusive total to find the pre-tax price and tax paid.

Salary Calculator

Convert pay between hourly, daily, weekly, monthly, and annual amounts based on your hours per week and weeks worked per year.

GPA Calculator

Calculate your weighted grade point average on a 4.0 scale from your course grades and credit hours, with each course counted by its weight.

Pregnancy Due Date Calculator

Estimate your pregnancy due date from your last menstrual period using Naegele’s rule, adjusted for your cycle length, plus how many weeks along you are.

Hours Calculator

Work out the time between a start and end time, subtract an unpaid break, and get the duration in hours and minutes and as a decimal for timesheets.

Pace Calculator

Calculate your running pace per kilometre or mile from distance and time, and see your average speed for training and race planning.

Temperature Converter

Convert temperatures instantly between Celsius, Fahrenheit, and Kelvin, with the exact conversion formulas shown for each pair.

Ideal Weight Calculator

Estimate your ideal body weight from height and sex using the Robinson, Devine, Miller, and Hamwi formulas, plus the healthy weight range for your height.

Body Fat Calculator

Estimate your body fat percentage with the U.S. Navy method from a few tape measurements, and see your body fat category and fat mass.

ROI Calculator

Calculate return on investment as a percentage from your cost and final value, plus the annualized return when you enter a holding period.

Fuel Cost Calculator

Work out the fuel cost of a trip from the distance, your vehicle’s fuel economy, and the price of fuel, in metric or imperial units.

Why CalcMate?

Most calculator sites bury the answer under popups and clutter. CalcMate does the opposite: each tool loads instantly, works entirely in your browser, and gives you the answer with a clear explanation of how it was calculated. Nothing you type is ever sent to a server or stored.

New calculators are added regularly. If there is a tool you would like to see, let us know.