Contact

Found a bug, spotted an error in a formula, or want to suggest a new tool? We read every message — and tool requests from teachers go to the top of the build list.

Email: [email protected] · we usually reply within two business days.

What to include

• Bug reports: the page URL, the numbers you entered and what you expected to see — with that, most fixes ship within days. Your device and browser help too.
• Formula disputes: we take these seriously. Point us to a source (textbook, official rule, regulator) and we'll verify against it — every formula on this site is covered by automated tests, so confirmed corrections stay fixed.
• New tool ideas: one sentence about the problem it solves beats a feature list. Our Hotel Nights Calculator started exactly this way.
• Embedding and partnerships: our widgets are free for any site, including schools and educational platforms — write if you need a variation.

A note on privacy

Your email is used only to reply to you — no lists, no newsletters, no sharing. And as everywhere on CalcNotebook, whatever you type into the calculators themselves never leaves your device.