About Number Anvil

Number Anvil makes free calculators for the sums people actually do: percentages, ages and dates, fractions, tips, BMI, GPAs and unit conversions. Each one works out the answer as you type, shows how it got there, and runs entirely in your browser, so nothing you enter is sent anywhere.

We care about getting the answer exactly right. Percentages, fractions and conversions use exact arithmetic rather than the rounded binary numbers most calculators use, dates are counted on the calendar rather than in milliseconds, and every formula and definition is explained on the page that uses it.

Number Anvil is made and operated by QRCat, LLC, which also makes Password Anvil, Money Anvil, QR Code Anvil, Pic Anvil and StaplePDF. The calculators are for general information; they are not medical, financial or legal advice.

Contact

Found a mistake, or want a calculator we don’t have? See the contact page.