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Income Tax · Personal Allowance

The 60% Tax Trap Nobody Talks About

Earn between £100,000 and £125,140 and your effective marginal income tax rate hits 60% — not 40%. One of the most punishing anomalies in the UK tax system, and most people who fall into it have no idea it exists.

Educational tip only. Not financial or tax advice. Individual circumstances vary significantly. If your income approaches or exceeds £100,000, you should consult a qualified tax adviser — the sums involved are material.
The Anomaly Explained

The UK Personal Allowance (£12,570 for 2025/26) is withdrawn above £100,000 at a rate of £1 of allowance for every £2 of income. The allowance reaches zero at £125,140. This means every pound earned in the £100,000–£125,140 band is taxed at 40% Income Tax as normal — but also triggers a loss of personal allowance that is itself taxed at 40%. Combined, the effective marginal rate on each of those pounds is 60%.

This is not a statutory rate — it appears nowhere in the tax legislation as "60%". It emerges from the interaction of two rules: the 40% higher rate and the taper mechanism. That is precisely why it goes unnoticed.

How UK Marginal Rates Actually Stack Up

The official tax rates present a misleadingly tidy picture. The reality, once the Personal Allowance taper is factored in, is a sharp and counterintuitive spike in the middle of the distribution.

Personal Allowance (£0–£12,570)0%
Basic rate (£12,571–£50,270)20%
Higher rate (£50,271–£99,999)40%
Taper zone — effective rate (£100,000–£125,140)60% effective
Additional rate (above £125,140)45%

Effective rates on income only. NI and dividend tax not shown. The 60% is the effective marginal rate in the taper zone, not a statutory rate.

60%Effective marginal rate between £100,000 and £125,140
£25,140Width of the 60% trap band
£5,028Maximum tax recoverable by restoring Personal Allowance via pension

A Worked Example

The mechanism is easiest to understand with a concrete example. Consider two employees: one earns £100,000, the other earns £102,000. The £2,000 salary difference should result in roughly £800 more take-home pay (£2,000 after 40% tax). It does not.

Earning £100,000 vs £102,000 — the real difference
Extra gross income£2,000
Income Tax at 40% on the extra £2,000£800
Personal Allowance lost (£2,000 ÷ 2 = £1,000)£1,000 allowance gone
Tax on the lost allowance (£1,000 × 40%)£400
Total additional tax on £2,000 extra income£1,200
Effective rate on that £2,00060%
Extra take-home pay for the £2,000 raise£800

The person earning £102,000 pays £1,200 more in tax than the person earning £100,000 — on just £2,000 more salary. Their net gain is only £800. This is why a £10,000 pay rise between £100,000 and £110,000 results in only £4,000 more take-home. The other £6,000 goes to HMRC.

The Pension Solution

The most widely used and effective response is to make pension contributions that bring your adjusted net income below £100,000. Pension contributions — whether via salary sacrifice, relief at source, or net pay arrangement — reduce adjusted net income, which is the figure HMRC uses to calculate how much Personal Allowance you retain.

✅ Example: Earning £110,000 — recovering the full allowance

Without pension contribution: Adjusted net income = £110,000. Personal Allowance = £12,570 − £5,000 taper = £7,570. You pay tax on £102,430.

With £10,000 pension contribution: Adjusted net income = £100,000. Personal Allowance = £12,570 (fully restored). You pay tax on £87,430.

Tax saving: The £10,000 pension contribution saves £6,000 in Income Tax (£10,000 at 40% plus £5,000 restored allowance at 40%). The contribution costs you only £4,000 net. £10,000 enters your pension; you are only £4,000 worse off in take-home. That is a 60% guaranteed upfront return — before any investment growth.

  1. Calculate your adjusted net income. Start with your gross income (salary, bonuses, rental income, interest) and deduct gift aid donations and pension contributions made under relief at source or net pay. Salary sacrifice reduces gross salary directly — it doesn't appear in adjusted net income because it was never part of it.
  2. Determine how much you need to contribute to reach £100,000. If your adjusted net income is £115,000, you need £15,000 in pension contributions (gross) to bring it to £100,000 and restore the full Personal Allowance.
  3. Make the contribution via salary sacrifice if possible. Salary sacrifice is the most efficient route — it reduces gross pay and also saves NI. If your employer doesn't offer salary sacrifice, contribute to a SIPP and claim the relief through self-assessment.
  4. File a self-assessment return. Anyone earning above £100,000 should be registered for self-assessment. If you are not already, register with HMRC. Your adjusted net income is calculated and reported there, and any additional pension relief (for higher rate taxpayers contributing via relief at source) must be claimed through self-assessment.
  5. Claim Gift Aid donations if applicable. Qualifying Gift Aid donations also reduce adjusted net income. If you already donate to charity, ensure you claim Gift Aid — it is deducted for taper purposes in addition to any pension contributions.
⚠️ The High Income Child Benefit Charge (HICBC)

If you or your partner receives Child Benefit and either of you earns above £60,000, a separate charge applies — the High Income Child Benefit Charge. Above £80,000, the entire Child Benefit is effectively clawed back. This creates an additional effective marginal rate for those in the £60,000–£80,000 band. Pension contributions that reduce income below these thresholds can also restore Child Benefit entitlement. This is another reason that individuals approaching these income levels should review their pension contribution strategy carefully with a qualified adviser.

Official Government & HMRC References
gov.uk — Income over £100,000: how the Personal Allowance is reduced gov.uk — How to calculate your adjusted net income gov.uk — High Income Child Benefit Tax Charge gov.uk — Who must send a Self Assessment tax return MoneyHelper — Income over £100,000 and the Personal Allowance trap
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