Contact

Email us at [email protected]. One person reads it, so plain email works better than a form.

Found an error?

Please tell us. It is the most useful message we get, and we would rather fix a formula than have someone rely on a wrong number.

To make it quick to verify, include:

• Which calculator, by name or link
• The exact values you entered
• The result you got, and the result you expected

If the disagreement is about a rate or a code limit rather than arithmetic, a link to the official source settles it fastest.

Requesting a calculator

Suggestions are welcome. Tell us what you are trying to work out and, if you can, what you currently do instead — a spreadsheet, a rule of thumb, calling someone. That usually reveals what the tool actually has to do.

Business enquiries

Advertising, licensing, or partnership questions can go to the same address. We do not accept paid guest posts, sponsored links, or link insertions, so please do not send those offers.

What we cannot do

We cannot give personalised financial, tax, legal, or engineering advice, review your specific situation, or tell you what you should do. The calculators are general reference tools — see our Terms of Use. For advice on your own circumstances, please speak to a qualified professional in your area.

Response time

Usually within a few days. Corrections get looked at first.