The Ultimate Calculator Collection

About Calcshark

Calcshark is a free directory of online calculators covering the numbers that come up in ordinary life and ordinary work: what a mortgage will actually cost, how much concrete a patio needs, whether a rental property makes money, how to scale a recipe for twelve instead of four. Every tool is free, none require an account, and the maths runs in your browser rather than on our servers.

The site is organised by category, so you can either search directly for what you need or browse from finance, health and fitness, construction, automotive, or any of the other categories on the category page.

A result you can check

A number without context is difficult to trust, so calculators here show their working. Where a formula has a standard behind it, the page names it. Where a result rests on an assumption, the assumption is stated rather than buried. Our guides and explainers go further and walk through the derivations in full, including the cases where a popular formula quietly gets things wrong.

Your inputs stay on your device

Almost every calculator runs entirely client-side. When you type a salary, a loan balance, or a set of body measurements, that data is processed by your browser and is not transmitted to or stored by us. That is a deliberate design choice, and it is set out in the privacy policy.

Calcshark is built and maintained by SEOShouts, a search consultancy based in India. If a calculator gives you a result that looks wrong, please tell us so we can fix it.