How work bonuses are taxed in the UK
In the UK, bonuses are treated by HMRC as taxable employment earnings, exactly like your regular salary. When your employer pays a bonus, it is added to your earnings for that pay period and processed through the PAYE (Pay As You Earn) system.
Because the bonus is added to your existing income, it is taxed at your highest marginal rate rather than your average tax rate. For example, if your base salary already uses up your tax-free Personal Allowance (£12,570), every pound of your bonus will be subject to Income Tax and National Insurance.
For basic rate taxpayers earning between £12,570 and £50,270, bonuses face a combined marginal deduction of 28% (20% Income Tax plus 8% employee Class 1 National Insurance). Higher rate taxpayers (£50,271 to £125,140) pay 40% Income Tax and 2% National Insurance (42% total).
If a bonus pushes your total annual income above £100,000, your tax-free Personal Allowance is reduced by £1 for every £2 earned above £100,000, creating an effective 60% marginal Income Tax rate (62% including NI) in the £100,000 to £125,140 bracket.
Worked example: £5,000 bonus on a £40,000 salary
Suppose your regular annual salary is £40,000 (£3,333.33 per month) and you receive a £5,000 cash bonus in a single monthly pay packet, with no pension sacrifice or student loan.
For Income Tax, your £40,000 salary leaves £10,270 of headroom in the 20% basic rate band before the higher rate threshold (£50,270). The entire £5,000 bonus falls in the basic rate band, incurring 20% Income Tax (£1,000.00).
For National Insurance, UK Class 1 NI is calculated on each pay period independently. In your bonus month, your gross pay rises to £8,333.33. The £855.84 between your normal monthly salary and the monthly Upper Earnings Limit (£4,189.17) is charged at 8% (£68.47). The remaining £4,144.16 exceeds the Upper Earnings Limit and is charged at the lower 2% rate (£82.88), giving total bonus NI of £151.35.
Total deductions on your £5,000 bonus are £1,151.35 (an effective marginal rate of 23.0%), giving you a net bonus take-home payment of £3,848.65 and total take-home pay of £6,541.95 in your bonus month.
Using bonus sacrifice to protect take-home pay and pensions
Many UK employers allow employees to sacrifice part or all of their bonus directly into their workplace pension scheme (known as bonus sacrifice).
By redirecting bonus payments into your pension before tax is calculated, you avoid both Income Tax and employee National Insurance on the sacrificed amount. Furthermore, many employers pass on some or all of their own 13.8% or 15% employer National Insurance savings into your pension pot as an extra contribution.
Inputs for the Bonus calculator
Annual base salary
Your contracted yearly gross salary before receiving the bonus.
Bonus calculation type
Choose whether your bonus is specified as a fixed cash lump sum or as a percentage of your salary.
Gross bonus amount
The gross cash bonus awarded before tax and statutory deductions (for fixed lump sum bonuses).
Bonus percentage
The bonus expressed as a percentage of your annual base salary (for percentage-based bonuses).
Pension deduction from bonus
Percentage of the bonus contributed or sacrificed into your workplace pension scheme.
Tax year
The UK tax year determining income tax bands, National Insurance thresholds, and student loan repayment limits.
Where you pay income tax
Select England, Wales, Northern Ireland, or Scotland (which has separate Scottish income tax bands and starter/intermediate rates).
Student loan repayment plan
Select your UK student loan plan (Plan 1, Plan 2, Plan 4, Plan 5, or Postgraduate loan) to deduct repayments above statutory thresholds.
CALCULATOR QUESTIONS
Bonus calculator questions
Why is my bonus taxed more heavily than my normal monthly pay?
Bonuses are added on top of your standard earnings in the pay period they are paid. Because your personal allowance is already spread across your base pay, the bonus is taxed entirely at your top marginal tax bracket.
Can I sacrifice my bonus into my pension to avoid tax?
Yes. If your employer offers a bonus sacrifice arrangement, you can pay some or all of your bonus directly into your pension tax-free, saving Income Tax and National Insurance.
Do student loan deductions apply to bonuses in the UK?
Yes. If your total gross pay in the pay period exceeds the weekly or monthly threshold for your student loan repayment plan, standard deductions (typically 9% of income above the threshold) will apply to the excess.
Will a bonus affect my Child Benefit?
If a bonus increases your Adjusted Net Income above £60,000, you will be subject to the High Income Child Benefit Charge (HICBC), phasing out Child Benefit fully by £80,000 unless offset by pension contributions.