Contact us

We welcome feedback, bug reports, tool requests, corrections and business enquiries. The fastest way to reach us is email:

What to include

• Bug reports: the tool's URL, what you entered, what you expected and what happened instead. Since tools run in your browser, your browser name/version helps too.
• Tool requests: what the tool should do and, if you know it, what you'd search on Google to find it.
• Corrections: if a formula, conversion factor or explanation looks wrong, point us at the page and the source you're comparing against.

We aim to reply within a few business days.