Online calculators
Calculators that show their working, grouped by what you are trying to find out. The math ones — Pythagorean theorem, probability and ratios — are the most searched.
Free · run in your browser · nothing uploaded
Geometry and algebra
Probability and statistics
Loans, savings and investing
Cooking
About these tools
A calculator is only useful if you can trust the method, so these pages explain the arithmetic rather than just printing an answer. That matters most where the intuitive approach is wrong: reversing a percentage is not the same operation as applying it, and an age in years, months and days is not a division by 365.25.
The set covers everyday arithmetic, money questions such as loans, discounts and pay, date and time differences, and basic statistics. Everything is computed locally as you type, so nothing you enter — a salary, a loan balance, a date of birth — is transmitted anywhere.
Questions people ask
Do these calculators show how the answer was worked out?
The math ones do: the Pythagorean, fraction, quadratic, logarithm, GCD and simple-interest calculators write out each step with your numbers substituted, and the triangle and Pythagorean calculators draw the shape to scale. That makes them usable for checking homework, not just getting a number.
How accurate are the health calculators?
They apply the standard published formulas — Mifflin-St Jeor for calories, the US Navy tape method for body fat, Naegele's rule for due dates — and say which one they use. Those formulas are population averages, so treat the result as an estimate rather than a diagnosis.
Is anything I type saved or sent anywhere?
No. The arithmetic runs in the page as you type. Salaries, loan balances and dates of birth are not transmitted or stored.