Your employer announces a £5,000 bonus. Champagne emoji. Then payroll runs it and your payslip looks like someone took a bite out of the bottle. Bonuses are not taxed at a special “bonus rate” — they are added to your taxable pay and hit at your marginal Income Tax and National Insurance rates. Sometimes student loan repayments join the party too.
How bonuses get taxed in the UK
For most PAYE employees, a bonus is simply extra earnings in the pay period it is paid. Your payroll system will:
- Add the bonus to your taxable pay for that month (or week)
- Deduct Income Tax using your tax code (usually cumulative — so earlier under- or over-payment can smooth out)
- Deduct employee National Insurance at 8% in the main band (£12,571–£50,270) and 2% above, for 2025/26
- Deduct student loan repayments if you are on a plan and total pay exceeds the threshold
There is no separate “bonus tax” percentage in law. When people say “bonuses are taxed at 40%”, they usually mean their marginal rate — basic 20%, higher 40%, or additional 45% — plus NI, not a flat bonus levy.
Marginal vs average rate
Your average tax rate is total tax divided by total income. Your marginal rate is what you pay on the next pound earned — and that is what governs a bonus.
On a £50,000 salary you might pay ~31% overall tax and NI. On an extra £5,000 bonus while you are still mostly in the basic band, the marginal hit might be closer to 28% (20% tax + 8% NI). Cross into higher rate and the marginal bite jumps toward 48% (40% + 8%) before student loans.
Worked example: £50k salary + £5k bonus
England/Wales/NI, 2025/26, standard code 1257L, no pension, no student loan:
The £5,000 bonus delivers about £2,940/year extra take-home (~£245/month) — not £5,000. Part of the bonus sits in the higher-rate band because total income exceeds £50,270, so 40% Income Tax applies to the slice above that line, plus NI throughout.
When a bonus pushes you into a higher band
Imagine you earn £48,000 and receive a £5,000 bonus. Total income is £53,000. Only £2,730 of the bonus sits above £50,270 — that portion faces 40% tax instead of 20%. The rest of the bonus is still taxed at basic rate plus NI. This “band straddling” is why two people with the same bonus amount can keep different percentages.
If your total income approaches £100,000, the personal allowance taper can make the marginal rate on a bonus painfully high — effectively 60% or more on some slices when you account for lost allowance. Bonuses near that cliff deserve a calculator, not optimism.
Student loans and pension on bonuses
Student loan repayments use 9% (undergraduate) or 6% (postgraduate) on pay above your plan threshold. A chunky bonus in one month can trigger a larger-than-usual SLC deduction. See our student loan guide for Plan 1/2/4/5 thresholds in 2025/26.
If you use salary sacrifice for pension, bonuses may or may not be included depending on your employer scheme. Sacrificed amounts reduce Income Tax and NI — useful for high earners. Our pension sacrifice guide covers the mechanics.
Why your first bonus payslip looks wrong
Payroll sometimes uses non-cumulative (month 1) tax on irregular payments, or emergency codes after a job change. That can make a single payslip look brutal even when your annual position is fine. HMRC usually corrects via your tax code or a Self Assessment refund if you overpaid. If you are on code BR, every pound is taxed at 20% with no allowance — see our emergency tax guide.
Bonus vs pay rise — different vibes, same maths
A permanent pay rise increases every future payslip. A bonus is a one-off with the same marginal rules. Comparing job offers? A £3k higher salary might beat a £5k bonus once you spread the tax bite across the year. Our pay rise guide shows how a £10k raise from £45k to £55k translates to roughly £545/month extra — not £833.
What actually matters before you celebrate
- Your salary band before the bonus (basic vs higher vs additional)
- Whether the bonus crosses £50,270, £100,000, or £125,140
- Employee NI — often forgotten in “I will keep 60%” mental maths
- Student loan and pension settings on payroll
- Whether the payment is cash, RSUs, or something with its own timing rules (this guide is PAYE cash bonuses)
Try a live example in TaxBite
Open the calculator with a £50k salary and a £5k bonus, or enter your own figures under Advanced Features. TaxBite shows bonus take-home, effective rate, and the overall Tax Bite so the celebration-vs-reality gap is obvious.
Open £50k + £5k bonus →Estimates only — not tax advice. Payroll timing, benefits, share schemes, and tax codes vary. Official PAYE guidance: gov.uk.