About

A collection of free calculators and converters for loans, retirement, investing, dates and time zones, maths, developer tasks and everyday units. Each one states the formula it uses and explains every symbol.

The calculation code is written and tested separately from the pages you see, and every result is computed in your browser. Where a real-world example was available, such as an actual loan repayment schedule, we checked the logic against it.

Precision is kept internally and numbers are rounded only when shown, so rounding never compounds into the answer.

We will not present a forecast as a guarantee, recommend a specific financial product inside a calculation, or blur the line between a neutral result and a sponsored one. If that ever changes, it will be labelled plainly.

Accuracy matters more than anything else here. If a result looks wrong, tell us with the Report a bug button at the bottom of any page — include the inputs you used, and a screenshot if you can — and we will investigate.