Threshold guide
£100k tax trap calculator
Who this helps
Who should use the £100k trap page
Why this taper matters before a general tax review
What this helps you decide
The trigger is ANI, not just salary
Salary alone is not the full story. Bonus, other taxable income, pension method, and Gift Aid all affect where ANI lands.
The taper starts at £100,000
Under current UK rules, Personal Allowance falls away once ANI goes above £100,000 and reaches zero by £125,140.
The band often feels like 60%
The allowance withdrawal adds extra income-tax drag inside the band, which is why people describe it as a 60% trap before NI or student loan is added.
ANI reducers are the practical fix
Gross pension contributions, Gift Aid, and salary sacrifice can all be useful because they reduce the threshold figure HMRC is testing.
Common questions
Why is it called the £100k tax trap?
Once adjusted net income goes above £100,000, your Personal Allowance falls by £1 for every £2 above the threshold. That creates a high effective marginal rate through the taper band.
When does the Personal Allowance taper end?
The taper ends once your Personal Allowance has been fully removed. Under the current standard allowance, that happens once ANI reaches £125,140.
Do pension contributions help with the £100k tax trap?
Yes. Qualifying pension contributions can reduce adjusted net income, which is why they are one of the main ways people move back below the taper start.
Is the effective rate always exactly 60%?
The core income-tax effect across the taper band is often described as 60%, but your real marginal drag can change once National Insurance and student loan deductions are involved.
Related calculators
Related calculators and guides for the same threshold problem
Adjusted Net Income calculator
Use the live ANI calculator when you want the exact gap above or below the taper start.
Gift Aid tax relief calculator
Use this when donations are one of the cleanest ways to pull ANI back below £100,000.
Salary sacrifice calculator
Use this when extra pension through payroll is the main fix you want to test.
Tax and payslip planner
Move into the broader tax planner when you want PAYE, balance due, and threshold planning in one place.
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