About Calcolia

Calcolia is a free collection of calculators for money, health, maths, business and daily life. Everything runs in your browser: the figures you type never leave your device.

Each calculator shows the formula it uses and a worked example you can check by hand. Where a result depends on national rules — a pension age, a VAT rate, the tax on investment gains — the rule is stated next to the result, with the date it was last reviewed.

The catalogue is deliberately small and growing. A calculator is published only once its maths is tested and its explanation is written in every language the site offers.