About Mathlark

Mathlark makes free calculators that show the work. Every result comes with the steps behind it, using your own numbers, so you can follow the math and check it for yourself.

How we check formulas

• Every formula is tested against worked examples from published sources, such as open textbooks and official standards. Each calculator page lists its sources at the bottom.
• The steps you see use exactly the same math as the result, never a separate calculation.
• Numbers are kept at full precision and only rounded when they're shown.

If you think something is wrong, please tell us.

Your numbers stay with you

Every calculation runs in your browser. Your numbers are never stored or sent anywhere. When you share a result, the numbers travel in the part of the link after the # sign, which browsers never send to a server.Read the full privacy page.

What we build

Only tools that run on pure math, so they don't go out of date: finance, math, health, and everyday calculators and converters. We don't build tools that depend on changing data like tax rules or exchange rates.