Most UK salary calculators give you a number and no way to check it. This one shows its work. Every rate comes from a named HMRC or gov.uk publication with the date it was last checked, the build fails if a rate set goes stale rather than quietly serving an old figure, and corrections are logged publicly with dates. The figures are independently verifiable. Reed publishes £35,000 as £28,719.60 after tax; The Accountancy Partnership publishes £50,000 as £39,519.60. This returns both to the penny.