About Numivo

Numivo is a free collection of online calculators for everyday tasks: planning a home project, working with percentages and dates, splitting a bill and more. There is nothing to install and no account to create.

How calculators are built

Each calculator is built around a small, separate piece of calculation code. That code is covered by automated tests that compare its output with values worked out independently, and with deliberately awkward input such as missing values, zero, negative numbers and very large numbers.

Unit conversions use exact published definitions, such as 1 inch = 2.54 centimetres and 1 pound = 0.45359237 kilograms. Where a result depends on an assumption, such as the density of a material, the calculator asks you for it instead of hiding a default.

Your data

Calculations run in your browser. The numbers you type are not sent to a server, and the site uses no cookies, analytics or advertising. See the Privacy Policy.

Corrections and contact

If a result looks wrong, please let us know. The Editorial Policy explains how calculators are checked and corrected.

Limitations

Results are estimates based on the numbers you enter and the assumptions explained on each page. For purchases, construction, financial or health decisions, check important figures with a qualified professional or your supplier. More in the Disclaimer.