About Calculators House

Calculators House is a library of free online calculators for everyday maths, personal finance, and time and date questions. It's run by Calculators House. There are currently 119 calculators across 15 categories.

What we're trying to do

Each calculator should answer one question quickly and show how it got there. You get the result, the formula, the working for your numbers, and the assumptions behind it, so you can check the answer and understand it rather than take it on trust.

Who the calculators are for

Anyone who needs a quick, transparent answer: checking a discount, comparing loan offers, counting days to a deadline or working out hours on a timesheet. The finance calculators give estimates for planning and comparison. They are not a substitute for a quote from a lender or advice from a qualified professional.

How we keep calculations accurate

The calculation code is kept separate from the written content, and every formula has automated tests covering normal values, edge cases and rounding. The worked examples on each page are generated by the calculator itself when the site is built, so the explanation and the tool can't disagree. Read more in how we calculate and our editorial policy.

Privacy by design

Calculations run in your browser. The numbers you type aren't sent to our servers or stored. See the privacy policy.

Contact

Found an error or want to suggest a calculator? Contact us. Corrections are our top priority.