512 free calculators, no sign-up

Calculators that show their working

Maths, money, science and everyday sums, each with its formula, a worked example and the working shown.

Popular:
Quick sumsWorks right here
%
20% of 150 is30
Open the full percentage calculator

Find your calculator by topic

See all 26 topics

Everyday favourites

How it works

1Type your numbersEvery tool opens with a real example filled in, so you can see how it works before you start.
2See the answer and whyResults update as you type, with the formula, a worked example and, where a method has steps, the working laid out.
3Keep or share itCopy the result, and on most tools share a link that reopens your numbers or print a clean summary.
Checked before it goes liveEvery calculator is tested against published reference values, and corrections are logged in public.
How we test