UK £100k Tax Trap Calculator – Personal Allowance Withdrawal 2026/27
Use this UK £100k Tax Trap Calculator to estimate how your Personal Allowance changes when your adjusted net income goes above £100,000. Enter your annual salary, bonus, current salary sacrifice, and any extra planned salary sacrifice to see whether you are inside the Personal Allowance taper zone and how much it may cost.
The calculator estimates your adjusted net income, Personal Allowance remaining, allowance lost, income tax, National Insurance, take-home pay, and the extra pension contribution that could bring you back below £100,000. To see your full salary breakdown first, use our UK Salary Calculator 2026/27.
UK £100k Tax Trap Calculator
Check how much of your Personal Allowance may be lost when your adjusted net income goes above £100,000. Estimate your income tax, National Insurance, take-home pay, and how much pension or salary sacrifice may bring you back below the tax trap.
Your Income
Enter your annual income before tax. Use yearly figures for the best estimate.
Quick Result
This summary shows your estimated position after your current and planned reductions.
| Adjusted net income | £0 |
|---|---|
| Personal Allowance left | £0 |
| Personal Allowance lost | £0 |
| Extra reduction needed to reach £100k | £0 |
Before vs After Extra Contribution
Compare your current position with the extra pension or salary sacrifice amount you entered.
| Result | Before extra | After extra |
|---|---|---|
| Adjusted net income | £0 | £0 |
| Personal Allowance | £0 | £0 |
| Income tax | £0 | £0 |
| National Insurance | £0 | £0 |
| Take-home pay | £0 | £0 |
Saving Breakdown
This shows how much tax and NI your extra contribution may save.
| Extra contribution tested | £0 |
|---|---|
| Estimated tax saved | £0 |
| Estimated NI saved | £0 |
| Net take-home reduction | £0 |
Important Notes
Calculator input scope: The two reduction fields model employer salary sacrifice only. They do not model Gift Aid or personal pension contribution mechanics.
What Is the £100k Tax Trap?
The UK £100k tax trap occurs when your adjusted net income exceeds £100,000. At this point, the standard Personal Allowance of £12,570 begins to be withdrawn at a rate of £1 for every £2 earned above the threshold. By the time income reaches £125,140, the full Personal Allowance is gone.
This creates an effective marginal tax rate of around 60% on income between £100,000 and £125,140 — because you are paying 40% Higher Rate tax on each extra pound earned, while simultaneously losing 50p of tax-free allowance for every £1 earned, making that allowance taxable too.
The 60% Tax Trap — Worked Example
Here is how the trap works in practice:
| Scenario | Income | Personal Allowance | Effective Rate on Extra £1 |
|---|---|---|---|
| Below threshold | £99,000 | £12,570 (full) | 40% |
| In the trap | £110,000 | £7,570 (£5,000 lost) | ~60% |
| Above the trap | £130,000 | £0 (fully withdrawn) | 45% |
Someone earning £110,000 has £10,000 above the threshold. That reduces their Personal Allowance by £5,000. The tax cost: 40% on the £10,000 extra income (£4,000) plus 40% on the £5,000 of allowance now taxable (£2,000) = £6,000 extra tax on a £10,000 pay rise — an effective rate of 60%.
How to Use This £100k Tax Trap Calculator
Enter your annual salary and any bonus or commission. Then enter current and planned salary sacrifice amounts to compare the estimate before and after sacrifice. The calculator treats reductions as salary sacrifice because personal pension and Gift Aid payments do not normally reduce employee National Insurance in the same way.
What Is Adjusted Net Income?
Adjusted net income is an HMRC measure based on total taxable income with specific adjustments. Pension contributions and Gift Aid can affect it, but the treatment depends on how the payment is made; salary sacrifice generally reduces contractual taxable pay before this calculation. It is adjusted net income — not salary alone — that determines whether the Personal Allowance is tapered. Check HMRC guidance or obtain professional advice for your circumstances.
Eligible pension contributions may reduce adjusted net income and restore some or all of the Personal Allowance. The amount entered and the tax treatment are not always the same: relief-at-source contributions are normally considered grossed up, while salary sacrifice changes taxable employment income. Confirm the correct amount with your pension provider, payroll team or HMRC.
Pension Contributions and the £100k Tax Trap
Eligible pension contributions can reduce adjusted net income, but the mechanics differ by contribution method. This calculator’s comparison fields are for employer salary sacrifice, which normally reduces taxable employment pay and employee National Insurance. Do not enter a relief-at-source personal contribution or Gift Aid payment as salary sacrifice.
Other items such as relief-at-source pension contributions and Gift Aid can affect adjusted net income, but they require different handling and are not modelled by the comparison fields in this calculator. For a full salary and take-home view, use our UK Salary Calculator and our Mortgage Calculator to see how income changes affect your borrowing capacity.
Bonus Payments and the £100k Threshold
Bonuses frequently push people unexpectedly into the trap. Someone earning £95,000 base with a £10,000 bonus reaches £105,000 — losing £2,500 of Personal Allowance and paying significantly more tax than expected on that bonus. Enter your bonus amount separately in the calculator to see the full impact.
Frequently Asked Questions
What is the 60% tax trap exactly?
For every £2 earned above £100,000, you lose £1 of Personal Allowance. That lost allowance becomes taxable at 40%. Combined with 40% Higher Rate tax on the extra income itself, the effective rate on gross earnings between £100,000 and £125,140 is approximately 60% before National Insurance.
Does a pension contribution reduce adjusted net income?
Yes. Both personal pension contributions and pension salary sacrifice can reduce adjusted net income. This may restore some or all of your Personal Allowance if it brings you below the £100,000 threshold.
At what income does the Personal Allowance disappear completely?
The standard Personal Allowance of £12,570 is fully withdrawn at £125,140 of adjusted net income. Above this level you pay 45% Additional Rate tax on all income with no Personal Allowance.
Does this calculator work for Scotland?
This version is designed for England, Wales, and Northern Ireland. Scotland has different income tax bands. The Personal Allowance taper still applies to Scottish taxpayers, but income tax calculations will differ.
Is this an official HMRC calculator?
No. This is a free estimation tool for planning purposes only. For a precise tax calculation, use the official HMRC calculator or consult a qualified tax adviser or accountant.
Related Finance Calculators
- UK Salary Calculator 2026/27 — See take-home pay after tax and NI across all salary levels
- Mortgage Calculator UK — Calculate monthly mortgage repayments
- Compound Interest Calculator — See long-term growth on pension and investment contributions
- Loan Calculator — Estimate loan repayments and total cost of borrowing
Official sources and review note
- GOV.UK: Income Tax rates for income over £100,000
- GOV.UK: adjusted net income
- GOV.UK: rates and thresholds for 2026/27
Scope: England, Wales and Northern Ireland; employment income estimate only. Last reviewed: 16 August 2026. See our editorial policy and methodology.
Important Disclaimer
This calculator is for general information and planning purposes only. It does not provide financial, tax, legal, pension, or professional advice. Tax rules can change, and your personal tax position depends on your tax code, pension type, employer scheme, student loan plan, residence, dividends, rental income, self-employment, and other individual circumstances. Always check with HMRC, your payroll team, a qualified accountant, or a regulated financial adviser before making important financial decisions.