If you are expecting a bonus this year, there is one thing almost every worker gets wrong: assuming the tax on a bonus is simply your normal tax rate. It is not. Bonuses are taxed in a way that can temporarily feel shocking — and understanding exactly why will help you plan for it, avoid nasty surprises, and even take steps to legally reduce the tax you pay.
1. Your bonus is taxed as ordinary employment income
There is no special "bonus tax" rate. Your bonus is added on top of your regular salary in the month it is paid, and the combined total is run through the same PAYE Income Tax and National Insurance bands as any other income. This means a £5,000 bonus paid in a single month will be calculated as if you earn £5,000 more that month.
For most basic rate taxpayers (earning under £50,270 a year), this means paying 20% Income Tax and 8% National Insurance on the bonus — a total marginal deduction of 28%. You keep roughly 72p of every £1 of bonus.
2. Large bonuses can temporarily push you into higher rate tax
This is the part that causes genuine shock. If your regular monthly salary is £4,000 (£48,000 annualised) and your bonus is £6,000, your total earnings for that month appear to be £10,000 (annualised to £120,000 for PAYE purposes). The payroll software will likely tax a chunk of your bonus at the 40% Higher Rate, plus the 2% NI Additional Rate.
The combined marginal rate on the portion above the Higher Rate threshold can reach 42%. However, because PAYE is cumulative, the system usually corrects itself the following month once it recalculates your actual annual income. You may not permanently overpay tax, but it can feel that way on your bonus payslip.
3. Salary sacrifice can legally eliminate tax on your bonus
This is the most powerful, and most underused, tax strategy available to UK employees. You can ask your employer to pay all or part of your bonus directly into your workplace pension as an employer pension contribution under salary sacrifice. Because the money goes into the pension before any tax is applied, you pay zero Income Tax and zero National Insurance on it. A £5,000 bonus paid into your pension costs the government £1,400 in tax savings — and you keep the full £5,000 working for your retirement instead of £3,600 in cash.
4. Child Benefit recipients face a bonus tax trap
If you or your partner claims Child Benefit and either of you earns more than £60,000 (the High Income Child Benefit Charge threshold), a large bonus can trigger a clawback of the entire Child Benefit amount. For example, a person earning £59,000 who receives a £5,000 bonus suddenly earns £64,000 — meaning they face both the 42% marginal tax rate on the bonus AND the loss of thousands of pounds in Child Benefit. This effective marginal rate can temporarily exceed 60%.
5. Bonuses affect your annual tax calculation
Your bonus is included in your total earnings when HMRC calculates your annual tax liability. If your employer's payroll software over-taxed your bonus in month one, PAYE will automatically claw it back through reduced tax deductions in subsequent months. By month 12, your total Income Tax paid should equal exactly what you owe. If you leave the job before the end of the tax year, however, any over-deduction on a bonus will be refunded either by your next employer (via the P45 cumulative system) or by HMRC at the end of the year through a P800 calculation.