Contact

Questions about the formulas, a result that looks wrong, or something the calculator should handle and doesn't.

Email

Email is the only channel. There is no contact form on this site, and that is deliberate: a form would mean sending what you type to a server, and the whole point of this calculator is that nothing you enter leaves your device.

Reporting a result that looks wrong

Accuracy is the only thing this tool has to offer, so a suspected error is the most useful message you can send. To make it quick to reproduce, include:

  1. Every value you entered, including anything under Advanced settings — overhead basis, fixed transaction fee, sales tax and price rounding all change the result.
  2. The figure the calculator showed.
  3. The figure you expected, and how you worked it out.

The quickest way to send the first two is the Copy results button under any result, which puts the full breakdown on your clipboard as plain text. Paste that into the email.

Before writing, it may be worth checking How we calculate. Two differences come up often and are working as intended: the price is found by dividing by (1 − margin − fee) rather than multiplying, and sales tax is never counted as your revenue.

What this page cannot help with

Nobody here can advise on your tax position, your accounts, or whether a specific price is right for your market. Those need a professional who can see your full picture. The calculator is arithmetic on figures you supply, and nothing about it is personalised advice.

Press and reuse

If you want to reference the tool or its formulas, everything is published openly on the How we calculate section — no permission needed to quote the method.