Contact

Email [email protected]. A real person reads every message.

Reporting a wrong result or outdated fee

So we can check it quickly, please include:

• the page address — the Copy link to this result button gives a link with your inputs in it;
• what you expected the answer to be, and why;
• for a fee, a link to where the platform publishes the new rate.

Suggesting a calculator

Tell us what you're trying to work out and what you'd enter. We build a new calculator when we can show the working, cite a source for every rate and make it more useful than what already exists.

Embedding a calculator

Each calculator page has an Embed this calculator button with code you can paste into your site. It's free; please keep the credit link.