Editorial policy and corrections

How a calculator is made

1. We start from the questions people actually ask, on forums and in search, and write down the situations the tool has to handle.
2. The rules come from the primary source: legislation, HMRC guidance and manuals, GOV.UK or the relevant employer handbook. We don't use other calculators as a source.
3. The calculation is written once, in shared code, with tests built from official and hand-worked examples.
4. A qualified reviewer checks the rules, the figures and the wording before the page is published.

Use of AI tools

We use AI tools to help draft code and copy. A person checks every figure against the source, and every page is reviewed before it's published. AI is never the source of a rate or a rule.

Independence and advertising

Advertisers have no say over what we write. Ads are labelled and are never placed between a calculator's inputs and its result. If we ever link to a product that pays us, the link will be marked as sponsored and explained next to it.

Corrections

If you think a figure is wrong, tell us with the inputs you used. We check reports against the source and aim to fix confirmed errors within two working days. Fixes are logged below.

Change log