£100k Tax Trap Calculator (UK, 2026/27)
Earn between £100,000 and £125,140? Your Personal Allowance shrinks by £1 for every £2 over £100,000, so each extra pound is taxed at an effective 60% (62% with National Insurance). See your rate, the rate at every £1,000 step, and how a pension contribution can bring your adjusted net income back to £100,000. Results update instantly. No sign-up.
England, Wales or Northern Ireland, tax code 1257L, NI category A, employment income only. Other income (savings, dividends, rent) also counts towards adjusted net income and isn't included.
- Adjusted net income (no pension)£0
- Personal Allowance (no pension)£0
- Gross pension to reach £100,000£0
- Adjusted net income with your pension£0
- Personal Allowance with your pension£0
- What the contribution costs you£0
Marginal rate from £80,000 to £150,000
Tax on each extra £1,000 of salary. Purple: Income Tax + NI. Dashed blue: Income Tax only. The hump between £100,000 and £125,140 is the allowance taper.
Your pension: with and without
The same salary with no pension and with your contribution. "Cost to you" is the drop in take-home pay, less any relief you claim back.
| Item | No pension | With your pension |
|---|
Quick answer
On a £110,000 salary in 2026/27 (England, Wales or Northern Ireland), the next £1,000 is taxed at 60% Income Tax plus 2% National Insurance: 62% in total. A gross pension contribution of £10,000 brings adjusted net income back to £100,000. Tax code 1257L, NI category A, employment income only, no other income. Rules from GOV.UK, checked 18 October 2026.
Every £1,000 step from £100,000 to £126,000
Each row runs the full take-home engine at both salaries and takes the difference. Your step is highlighted.
| Salary step | Allowance at start | Extra Income Tax | Extra NI | Income Tax rate | With NI |
|---|
Why the rate is 60%
GOV.UK: “Your personal allowance goes down by £1 for every £2 that your adjusted net income is above £100,000. This means your allowance is zero if your income is £125,140 or above.” Between those figures, each extra £1 is taxed at 40%, and it also removes 50p of tax-free allowance, which is then taxed at 40% too: 40p + 20p = 60p in every pound. Add 2% employee National Insurance above £50,270 and it is 62%; a student loan adds 9% more. Above £125,140 the allowance is gone and the rate drops to 45% (47% with NI).
Over the whole band, £25,140 of extra salary costs £5,028 more in tax than a flat 40% would (the £12,570 allowance at 40%).
Adjusted net income and pensions
The taper works on adjusted net income, not your salary. GOV.UK's adjusted net income guidance says to take off pension contributions where your provider has already given you basic rate relief: “take off the ‘grossed-up’ amount — what you paid plus the basic rate of tax.” So:
- Salary sacrifice lowers your pay itself, so Income Tax, NI and adjusted net income all fall. At £110,000, sacrificing £10,000 restores the full allowance and costs £3,800 of take-home pay for £10,000 in the pension.
- Relief at source: you pay £8,000, your provider adds £2,000, and adjusted net income falls by the £10,000 gross. Payroll still taxes the full salary, so you claim back the higher-rate relief (£2,000) and the value of the restored allowance (£2,000) through Self Assessment or HMRC. The cost is £4,000: the £200 difference is the NI salary sacrifice also saves.
The calculator runs both through the same engine as our take-home pay calculator, so the figures match it to the penny. Pension contributions count towards the annual allowance (£60,000 for most people), and the money is not available until your pension scheme allows, usually not before 55.
What this calculator does not cover
- Other income that counts towards adjusted net income (savings interest, dividends, rent, self-employment) and Gift Aid, which also lowers it.
- Scottish Income Tax: the same taper applies but the rates differ.
- Childcare support that depends on income, and the High Income Child Benefit Charge.
- Employer pension contributions, and any employer NI savings passed on under salary sacrifice.
The formula
- Marginal rate on a step = (tax and NI at the higher salary − at the lower salary) ÷ £1,000
- Gross pension to restore the allowance = adjusted net income − £100,000
- Cost to you = fall in take-home pay − relief you claim back (relief at source only)
See the formula with your own numbers
These update live from the calculator inputs above.
Frequently asked questions
What is the £100k tax trap?
Between £100,000 and £125,140 of adjusted net income, your Personal Allowance goes down by £1 for every £2 over £100,000 (GOV.UK). Each extra pound is taxed at 40% and also loses 50p of allowance, so the effective Income Tax rate is 60%, or 62% with 2% National Insurance.
How much pension do I need to pay to avoid the 60% tax rate?
Enough to bring adjusted net income down to £100,000. With no other income, that is your salary minus £100,000 as a gross contribution: £10,000 on a £110,000 salary. Under relief at source you pay 80% of that and your provider adds the rest.
Is salary sacrifice or relief at source better for the £100k trap?
Both restore the allowance. Salary sacrifice also saves 2% National Insurance, so £10,000 into the pension at £110,000 costs £3,800 of take-home pay, against £4,000 under relief at source. With relief at source you claim the higher-rate relief and the restored allowance back through Self Assessment or HMRC.
At what salary is the Personal Allowance zero?
At £125,140 of adjusted net income and above. From there, income over £125,140 is taxed at the 45% additional rate.
What counts as adjusted net income?
GOV.UK: total taxable income before Personal Allowances, less certain reliefs, including the grossed-up amount of pension contributions that already got basic rate relief and of Gift Aid donations. Salary sacrifice lowers your taxable pay directly.
Method & sources
- Calculation:
thCompute(the engine behind our take-home pay calculator) at each salary in £1,000 steps; the marginal rate is the difference in Income Tax and NI ÷ £1,000. Pension contributions run through the same engine (salary sacrifice lowers pay; relief at source lowers adjusted net income and reports higher-rate relief and restored allowance). - Personal Allowance taper (£1 for every £2 over £100,000; zero at £125,140): GOV.UK — gov.uk/income-tax-rates.
- Adjusted net income (grossed-up pension contributions): HMRC — gov.uk/guidance/adjusted-net-income.
- Relief at source and higher-rate relief; annual allowance: GOV.UK — pension tax relief and annual allowance. Salary sacrifice: HMRC — salary sacrifice and the effects on PAYE.
- Pension access usually not before 55: GOV.UK — early retirement: personal and workplace pensions.
- Employee National Insurance 2026 to 2027: GOV.UK — gov.uk/national-insurance-rates-letters.
- All sources checked 18 October 2026. Verification: automated tests, run before every update, check the results against hand-worked examples and confirm every tax and National Insurance figure comes from the same tested engine as our take-home pay calculator.
- Reviewed: .
Educational estimate only, not personal financial, tax or pension advice. Your adjusted net income includes other income not entered here, and pension rules depend on your scheme. Rules can change; confirm with GOV.UK, HMRC or a regulated adviser.
Run your own numbers
Enter your salary and a pension contribution to see your marginal rate and what restoring the allowance costs.
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