What is the £100k tax trap?
When adjusted net income rises above £100,000, the Personal Allowance is reduced by £1 for every £2 above the threshold. That creates a high marginal income tax zone before the allowance is fully removed.
How to use this page
Enter a salary above £100,000, then try different salary sacrifice pension percentages to see how adjusted income and Personal Allowance change.
More salary examples
Extra annual salary examples are tucked away here to keep the main calculator page clean. These buttons still use annual salary mode, not hourly mode.
Frequently Asked Questions
Which tax year does this calculator use? +
It uses the 2026/27 UK tax year for England, Wales and Northern Ireland estimates.
Does salary sacrifice reduce National Insurance? +
In this calculator, yes. The pension percentage is treated as salary sacrifice, so the reduced cash pay is used for both income tax and employee National Insurance estimates.
Does this include Scottish income tax? +
No. Scottish income tax rates and bands are different and are not included in this version.
Why might my payslip be slightly different? +
Payroll systems use pay-period thresholds, tax codes and rounding rules. This calculator gives a strong annual estimate, not payroll advice.