About Calculatrixe
Calculators that show their formula, state their assumptions and keep what you enter on your own device.
What it is
Calculatrixe is a growing collection of free online calculators. There are 42 so far, and each has its own page with the calculator itself, the formula it uses, a worked example computed by the same code, its assumptions and limits, and answers to the questions people usually ask.
How your numbers are handled
Every calculation runs in your web browser using JavaScript. The numbers and dates you enter are processed on your device and are not sent to our servers, saved or logged. There are no accounts and nothing to sign up for. Once a page has loaded, it keeps working with your network disconnected.
Why accuracy matters here
Computers store most decimals in binary, which is why 0.1 + 0.2 comes out as 0.30000000000000004 in many programs. Where that could reach a result, Calculatrixe works with exact decimals instead. When a result has to be rounded, the page says that it was rounded, and how. Date calculations use calendar arithmetic rather than time zones, and each page lists the conventions it follows, such as how a 29 February birthday is counted. If you find a result that looks wrong, please tell us.
How it is funded
Calculatrixe is free to use and is supported by advertising. Advertisements are labelled, kept away from the inputs and results, and are never placed where they could be mistaken for a button or an answer. See the Privacy Policy for what advertising partners may collect when ads are shown.