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£100k Tax Trap & Salary Sacrifice Calculator 2026/27

Analyze your 60% effective marginal tax rate on income between £100,000 and £125,140. See how much Personal Allowance you lose and how pension contributions eliminate the trap.

✅ Official 2026/27 Statutory Rates 🎁 100% Free Calculator 💼 Childcare Cliff Warnings

⚡ At a Glance: The £100k Penalty Benchmark

Statutory 2026/27

Between £100,000 and £125,140, HMRC withdraws £1 of your £12,570 tax-free Personal Allowance for every £2 of income. This creates a hidden 60% Income Tax rate (62% with NI). In addition, crossing £100k forfeits up to £2,000/child Tax-Free Childcare and 30 free hours.

Income Level Personal Allowance Marginal Rate Effective Tax Relief on Pension Childcare Subsidies
£100,000 (Baseline) £12,570 (100%) 42% (40% IT + 2% NI) 40% Higher Rate 100% Eligible
£110,000 (Inside Trap) £7,570 (Lost £5,000) 62% (60% IT + 2% NI) 60% Effective Relief £0 (Cliff-Edge Lost)
£125,140+ (Full Taper) £0 (100% Lost) 47% (45% IT + 2% NI) 45% Additional Rate £0 (Cliff-Edge Lost)
Related High-Earner Calculators: Childcare Cliff • Bonus Over £100k • Pension Relief

Live £100k Tax Trap & Pension Relief Modeler

Adjusted Net Income
£100,000
Full Allowance Restored
Personal Allowance Kept
£12,570
Max £12,570 statutory limit
Marginal Tax Rate
42%
Trap Avoided
Annual Tax Saved by Pension
£9,300
Effective 62% tax relief
👶
Tax-Free Childcare & 30 Free Hours Protected!
Adjusted net income is at or under £100k, safeguarding your government subsidies.
Calculate Childcare Loss →

Step-by-Step Worked Mathematical Examples

The calculations below illustrate exact progressive Income Tax, National Insurance, and Personal Allowance taper formulas for 2026/27.

Unplanned Bonus

£110,000 Salary (No Pension Sacrifice)

Gross Earnings: £110,000

Personal Allowance Lost £1 per £2 over £100k (£10k / 2)
−£5,000
Remaining Tax-Free Allowance £12,570 − £5,000
£7,570
Extra Tax on £10k in Trap 40% IT (£4,000) + 20% Taper (£2,000) + 2% NI (£200)
£6,200
Marginal Deduction Rate 62.0%

Out of the £10,000 earned between £100k and £110k, the worker keeps only £3,800 in cash.

Salary Sacrifice

£110,000 Salary + £10,000 Pension

Adjusted Net Income: £100,000

Full Personal Allowance Retained Income reduced to £100,000 threshold
£12,570
Immediate Tax Relief 40% Higher Rate (£4,000) + 20% Allowance (£2,000)
−£6,000
Employee NI Saved (if Salary Sacrifice) 2% on £10,000 contribution
−£200
Net Cost of £10,000 Pension Pot £3,800

Contributing £10,000 to pension costs only £3,800 in forgone take-home pay, an instant 163% return.

Full Allowance Loss

£125,140 Salary (100% Taper Peak)

Gross Earnings: £125,140

Personal Allowance Remaining Full £12,570 tapered away
£0.00
Total Tax on the £25,140 Band 60% Income Tax + 2% NI across full band
£15,586.80
Total Take-Home on £125,140 Net after £37,428 IT and £3,341 NI
£84,370
Cumulative Marginal Trap Cost £15,586.80

Above £125,140, the marginal rate drops back down to 47% (45% Additional Rate + 2% NI).

Frequently Asked Questions About the £100k Tax Trap

What is the UK £100k tax trap in 2026/27?

The £100k tax trap is an effective 60% Income Tax rate on earnings between £100,000 and £125,140. For every £2 earned over £100k, you lose £1 of your £12,570 Personal Allowance. Combined with 2% National Insurance, your true marginal deduction rate is 62%.

How do you avoid the 60% tax trap over £100k?

You avoid the 60% tax trap by paying into a pension via salary sacrifice or SIPP to bring your adjusted net income back to £100,000. This restores your full Personal Allowance and yields 60% tax relief on your contribution.

Does earning over £100,000 affect tax-free childcare?

Yes. Earning even £1 over £100,000 in adjusted net income triggers a complete cliff-edge loss of Tax-Free Childcare (up to £2,000 per child) and 15 to 30 hours of free childcare worth thousands per year.

Does a bonus push you into the 60% tax trap?

Yes. Discretionary bonuses are added directly to your gross salary. If your base salary is £95,000 and you receive a £15,000 bonus, your total earnings reach £110,000, subjecting £10,000 of your bonus to the 62% marginal deduction rate.

Statutory Authority: Income Tax Act 2007, Section 35 (Personal Allowance reduction for income exceeding £100,000) & HMRC Guidance on Adjusted Net Income. Verified for the 2026/27 UK tax year.