Bonus tax calculator for the UK
See the final annual Income Tax effect and the actual bonus-month employee National Insurance and student-loan deductions, then estimate what the payslip may show under cumulative PAYE.
This models an ordinary employee paid the same salary each month and a one-off cash bonus. It is not a flat “bonus tax” rate: HMRC treats the bonus as earnings and adds it to pay.
How much of a bonus do you keep?
On a £60,000 salary in England, Wales or Northern Ireland, a £10,000 cash bonus leaves about £5,800 after final annual Income Tax and the bonus month payroll deductions: £4,000 Income Tax and £200 employee NI.
A cash bonus counts as earnings. Employers add it to other earnings and deduct PAYE Income Tax and Class 1 National Insurance through payroll, rather than applying a special flat bonus rate. HMRC’s bonus guidance states that rule directly. The amount you lose depends on which annual tax bands and which monthly payroll thresholds the bonus crosses.
Why the annual answer and the payslip can differ
The green result combines the final tax-year Income Tax difference with the actual bonus-month NI and student-loan differences. Income Tax uses the final Personal Allowance and annual bands because HMRC can reconcile it. NI and student loans stay pay-period based. The payslip panel is a separate timing estimate. It assumes tax code 1257L, C1257L for Wales or S1257L for Scotland, used cumulatively in the selected tax month.
On a cumulative code, payroll uses a growing share of the allowance and tax bands and considers pay and tax already recorded in the year. HMRC describes this as a rolling basis up to each payday. HMRC PAYE manual. The estimate therefore starts with equal monthly salary from April and puts the full bonus into the one month selected above.
NI and student-loan deductions are different. For an ordinary monthly-paid employee they use that month’s pay and thresholds, so the payslip panel applies the monthly thresholds directly instead of annualising them. Student and postgraduate loan deductions are rounded down to whole pounds for each plan. A real payslip may still differ slightly.
The monthly thresholds used on the bonus payslip
The calculator adds regular monthly salary and the cash bonus before applying these pay-period thresholds. Only the incremental difference from the same month without the bonus is labelled “of the bonus”.
| Deduction | Monthly threshold / band | Rate |
|---|---|---|
| Employee NI | £1,048–£4,189 | 8% |
| Employee NI | Above £4,189 | 2% |
| Student loan Plan 1 | Above £2,241.66 | 9% |
| Student loan Plan 2 | Above £2,448.75 | 9% |
| Student loan Plan 4 | Above £2,816.25 | 9% |
| Student loan Plan 5 | Above £2,083.33 | 9% |
| Postgraduate loan | Above £1,750 | 6% |
Primary sources: HMRC employer rates and thresholds and student and postgraduate loan guidance for employers.
Bonuses around the £100,000 Personal Allowance taper
From £100,000 of adjusted net income, the Personal Allowance falls by £1 for every £2 of extra income. It reaches zero at £125,140. A bonus inside this span can therefore create 60% effective Income Tax in England, Wales and Northern Ireland before NI or a student loan is added. gov.uk: income over £100,000.
For example, a £10,000 bonus on a £100,000 salary leaves about £3,800 in the annual comparison: the bonus creates £6,000 of Income Tax and £200 of employee NI.
The first payslip may not show the full taper cost
The payslip estimate holds a standard 1257L code constant. That code does not model the Personal Allowance taper itself, so HMRC may later change the code or reconcile tax after the year. Use the annual result for the taper, and the payslip result only as an estimate of what the selected payroll run may deduct.
Scotland and threshold crossings
Scottish taxpayers pay Scottish Income Tax on employment income. Selecting Scotland uses the six 2026/27 bands in the annual calculation and approximates an S1257L cumulative code on the payslip. Scottish Income Tax rates. The calculator calls out a band crossing instead of pretending the whole bonus has one rate.
Employee NI and student-loan thresholds are UK-wide. Region changes the Income Tax part, not those payroll deductions.
When this estimate will not match payroll
Your tax code is not 1257L
Benefits, earlier underpayments, a second job, Marriage Allowance, a K code, BR/D0/D1, or an emergency Month 1 code all change PAYE. A Month 1 code ignores earlier pay and tax, unlike this cumulative estimate. Check emergency tax codes on gov.uk.
You are a company director
Directors’ NI is normally based on annual earnings, with special standard and alternative methods. The ordinary monthly NI calculation above is not suitable for a director. National Insurance for company directors.
Your pay is weekly or irregular
The tool assumes twelve equal salary payments and one monthly bonus. Weekly, four-weekly, multiple-job, late, corrected or irregular payments use different earnings periods or cumulative records. Payroll software has the definitive figures for that run.
You sacrifice bonus into a pension
This calculator assumes the cash reaches payroll as earnings. A valid employer salary- sacrifice arrangement can reduce taxable and NI-able pay, but scheme rules, timing and pension allowances matter. Model the alternative in the salary sacrifice calculator.
Sources and disclaimer
Informational estimates based on 2026/27 rates, not financial or tax advice. Income Tax is an annual comparison; NI and loans are pay-period calculations, and HMRC may reconcile Income Tax later. Confirm a high-value or unusual payment with payroll or a tax adviser.