1. How the 60% Tax Trap Works (The Personal Allowance Taper)
Under the Income Tax Act 2007 (Section 35), every UK taxpayer receives a standard tax-free Personal Allowance of £12,570 (tax code 1257L). However, once your Adjusted Net Income (ANI) exceeds £100,000, HMRC reduces your Personal Allowance by £1 for every £2 earned above £100,000 until it reaches £0 at £125,140. Because every £100 earned in this band triggers £40 of direct 40% Higher-Rate Income Tax plus £20 of tax on the £50 of withdrawn Personal Allowance, your effective Income Tax rate is 60%—or 62% including 2% Class 1 Employee National Insurance (and 71% with a Plan 2 or Plan 5 Student Loan).
2. The Childcare Cliff-Edge: The Real Financial Disaster
Unlike the Personal Allowance taper, UK childcare support operates as an all-or-nothing cliff-edge at £100,000 of individual Adjusted Net Income. Earning £100,001 disqualifies a household from Tax-Free Childcare (worth up to £2,000 per child per year) and 30 Hours of Funded Childcare for working parents of children aged 9 months to 4 years (worth £4,500 to £7,500+ per child per year).
3. Case Study: The £5,000 Pay Rise That Cost £14,000
At £100,000 Adjusted Net Income, exact 2026/27 HMRC Income Tax is £27,432.00 (£7,540 Basic + £19,892 Higher) and Class 1 NI is £4,010.60 (£3,016 main + £994.60 upper), totaling £31,442.60 in tax and NI and leaving £68,557.40 net take-home pay. Rising to £105,000 adds £1,900.00 net pay (£70,457.40 net), but forfeits £4,000 in Tax-Free Childcare and £11,900 in Funded Childcare hours—leaving the family £14,000.00 worse off (£84,457.40 vs £70,457.40).
| Annual Financial Line Item (2 Children in Nursery) | At £100,000 ANI | At £105,000 ANI (+£5k Raise) | Net Impact |
|---|---|---|---|
| Income Tax & Class 1 NI (1257L) | -£31,442.60 | -£34,542.60 | -£3,100.00 (62%) |
| Net Payslip Take-Home Pay | £68,557.40 | £70,457.40 | +£1,900.00 |
| Tax-Free Childcare (2 Children) | +£4,000.00 | £0.00 | -£4,000.00 |
| 30 Hours Funded Childcare Value | +£11,900.00 | £0.00 | -£11,900.00 |
| Net Household Cash After Childcare | £84,457.40 | £70,457.40 | -£14,000.00 WORSE OFF |
4. FAQ Section & Checklist Before 5 April
Does an annual cash bonus or overtime push me over the £100,000 childcare and 60% tax trap threshold?
Yes. HMRC assesses the Personal Allowance taper and Tax-Free / 30-Hour Funded Childcare eligibility on your total Adjusted Net Income (ANI) for the tax year (6 April to 5 April), not your base salary alone. If your base salary is £92,000 and you receive a £12,000 annual bonus in March, your total gross income is £104,000. Unless you contribute at least £4,000 gross into a workplace pension, personal SIPP, or Gift Aid before 5 April, you will breach the £100,000 cliff-edge, lose £2,000 of your Personal Allowance, and forfeit Funded Childcare eligibility.
Do vested RSUs (Restricted Stock Units), share options, and P11D company benefits count toward Adjusted Net Income?
Yes. When Restricted Stock Units (RSUs) vest or non-tax-advantaged share options are exercised, their market value on the vesting date is treated as employment income subject to PAYE and is included in full within your Adjusted Net Income.
If I make a one-off personal SIPP contribution in March, when is the deadline and how do I claim the 40%–60% tax relief?
To reduce your Adjusted Net Income for a given UK tax year, your personal SIPP contribution must clear into your pension provider's account on or before 5 April (at 23:59). When you pay into a personal SIPP (Relief at Source), you deposit 80% of the target gross amount—for example, paying £8,000 cash automatically becomes £10,000 gross inside your SIPP after the provider claims 20% Basic Rate relief (£2,000) from HMRC.
What happens if one parent earns £105,000 and the other parent earns £25,000 — do we still lose 30 Hours Funded Childcare?
Yes. Both Tax-Free Childcare (£2,000/year per child) and the 15/30 Hours Funded Childcare scheme in England are assessed strictly on an individual parent basis, not combined household income.