Reporting a problem
Please include:
- the calculator's page link,
- a share link with your inputs (use “Copy link to these numbers” under the calculator), or the numbers you entered,
- the result you got and the result you expected, with its source if you have one.
Don't send passwords, card numbers or other private details. A share link puts your inputs in the address, so leave out anything you'd rather keep private.
Suggesting a calculator
Tell us what you want to work out and where you live, so we can use your country's rules and units.
Last updated 25 October 2026.