Calculators for Every Question.

Yes. All 14 calculators are free to use as often as you like, with no account, no trial period and no premium tier. There is nothing to download or install — open a calculator in any modern browser and start typing.

Every calculation runs inside your own browser. The numbers you type — your salary, loan amount, weight or grades — are never sent to a server, stored in a database or shared with anyone.

The site sets no tracking cookies. The only things saved are on your own device: your light or dark theme choice, and the GPA calculator's course list so it is still there next time — which you can clear with one click.

Each calculator uses the standard published formula for its job — the amortisation formula for loans, the law of cosines for triangles, Bessel's correction for sample standard deviation — and every formula is checked by hundreds of automated tests against textbook values and edge cases.

Fraction arithmetic is exact at any size, and money is rounded to the cent only at the final step. Results are for general information: for legal, medical or financial decisions, confirm important figures with a qualified professional.

Yes. The site is designed mobile-first: number fields bring up a numeric keypad, buttons are large enough to tap accurately, and pages are small static files that load quickly on a weak connection. Dark mode follows your device settings automatically.

Because the maths runs on your device, there is no need to wait for a server. Results refresh on every keystroke, so you can change one number and immediately see how it affects the answer — useful for comparing loan terms, tip percentages or discount scenarios.

Most calculators show their working. The percentage, fraction and standard deviation calculators list each step, the compound interest calculator includes a year-by-year breakdown, the loan calculator shows what paying extra would save, and every calculator page explains its formula with worked examples you can follow by hand.

Use the search box at the top of the page (or press Ctrl K) and type what you want to work out, such as “split a bill”, “days between dates” or “square root”. For general maths, the scientific calculator handles trigonometry, logarithms, powers and roots. If you cannot find the tool you need, use the contact page to suggest it.