UK 60% Tax Trap Calculator — Methodology

Last verified 5 May 2026 against HMRC personal allowance taper guidance (EIM01200). Calculator at /uk/tax/60-percent-tax-trap-calculator/.

What this calculator does

Models the marginal effective tax rate of 60% (61.5% in Scotland) that applies between £100,000 and £125,140 due to the personal allowance taper, and shows how pension contributions can reclaim the trapped allowance.

The formula

PA_taper = max(0, £12,570 - max(0, ATI - £100,000) / 2)
PA_lost  = £12,570 - PA_taper

Marginal rate in £100k–£125,140 band:
  Each extra £1 of income loses £0.50 of allowance, which
  is taxed at the higher rate (40% rUK or 42% Scotland).

  rUK:      40% on £1 + 40% × £0.50 = 60% effective
  Scotland: 42% on £1 + 42% × £0.50 = 63% effective

Pension reclaim:
  ATI for taper purposes = grossSalary - grossPensionContrib
  Contributing into the band restores PA at marginal rate.

Authoritative sources

• Personal Allowance taper (HMRC manual EIM01200)
• Income Tax rates and Personal Allowances
• Tax on your private pension contributions
• Scottish Income Tax

Assumptions and limitations

• Adjusted net income (ATI) is approximated as gross salary less gross pension contributions; gift aid and other deductions are not modelled.
• Assumes the user has the full standard personal allowance (1257L); marriage allowance transfers and blind person's allowance are out of scope.
• The Scottish 'advanced rate' band of 45% above £75,000 means the trap effective rate in Scotland is shown for the higher (42%) band only.
• Employee NI within the trap band (currently 2% above the upper earnings limit) is treated separately and not added to the headline 60%/63% figure.

Source data

The rates used by this calculator are exported as machine-readable CSVs:

• Income tax rUK 2026/27 /data/income-tax-rUK-2026-27.csv
• Income tax Scotland 2026/27 /data/income-tax-scotland-2026-27.csv

These CSVs regenerate automatically from our canonical rate data at every build, ensuring the calculator output and the published rate data stay in sync.

Verification log

• 5 May 2026: PA taper threshold and rate verified against EIM01200; rUK and Scottish band interaction confirmed