Corrections policy
Getting the numbers right matters more than anything else on this site. When we get something wrong, we fix it openly.
How to report a mistake
Email us at [email protected]. Tell us which page you were on, what you entered, and the figure you expected, with a source if you have one. The contact page has more detail.
What we do next
- We check it against the primary source. We compare the figure with the GOV.UK or HMRC page it comes from, never with another calculator or a blog.
- We fix the cause, not just the page. If a rate or threshold is wrong, we correct it in our rules data, so every calculator and page that uses it is fixed at once. If the method is wrong, we correct the code and add a test so the same mistake cannot come back.
- We record the change. Corrections that changed a result are listed, with the date, on our How we calculate page.
- We reply to you to say what we found, whether or not we changed anything.
What counts as a correction
A correction is any change that fixes a wrong result, a wrong figure or a misleading explanation. Routine updates, such as new rates for a new tax year, are not corrections. Those are part of our normal yearly update and are shown by the "last checked" date on each page.
If a result is different from your payslip
Small differences are expected and are not usually a mistake. Our calculators work on yearly figures, while payroll works out each pay period separately. The How we calculate page explains why. If the difference is large, please tell us.