Free online calculators and converters for everyday math: percentages, discounts, loans, compound interest, tips, BMI, ages, dates, work hours, units, temperature, aspect ratios, numbers in words, Roman numerals and time zones, plus two calculators for Instagram creators. Pick one below, enter your numbers and get the answer instantly. Everything runs in your browser and nothing is uploaded.
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About the Calculators
Each calculator does one job and shows the result as you type. There is nothing to install and no sign-up. They work on phones, tablets and computers.
Which Calculator Do I Need?
Money and shopping
Use the discount calculator to see the price after a sale and the tax, the percentage calculator to compare two prices, and the loan calculator to see what a loan will really cost with interest.
Savings and splitting a bill
The compound interest calculator shows how a deposit grows over the years, and the tip calculator works out the tip and each person’s share of a restaurant bill.
Health
The BMI calculator turns your height and weight into a body mass index and shows the standard range it falls in. It is a general guide, not medical advice.
Dates and time
The age calculator, the days between dates calculator and the hours calculator help with birthdays, deadlines, trips and timesheets.
Converters
The unit converter and the temperature converter handle measures, the time zone converter compares times between cities, the aspect ratio calculator helps you resize pictures and videos, and the number to words and Roman numerals tools change how a number is written.
Social media
The Instagram money calculator and the Instagram engagement rate calculator give creators quick numbers for planning and for talking to brands.
Tips for Accurate Results
- Double check the numbers you type, especially decimals and dates.
- For loans, use the yearly interest rate and the full length of the loan.
- Results are estimates for planning. For legal, tax, medical or financial decisions, ask a qualified professional.
Frequently Asked Questions
Are these calculators free?
Yes. All of them are free, with no sign-up.
Do you save the numbers I enter?
No. The calculations run in your browser and nothing is sent to our servers.
Can I use them on my phone?
Yes. The pages are built to work on small screens.
Are the results exact?
The math is exact for the numbers you enter. Real life can differ, for example a bank may round or add fees, so treat results as estimates.
More Free Tools
Browse all free online tools, or try the word counter, the color converter and the image converter.