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The £100k / 60% tax trap calculator

See the modelled cost of a pension contribution at your target income.

Free, no sign-up. AI never does the maths.

Additional illustrated contribution£18,000

See the working
Worked example. Gross contribution, modelled net cost £7,200

Whole tax year, gross, using the method above. £0 if none.

Why we ask
The amount already being made this tax year using the selected method. The result shows the additional contribution needed. If existing contributions use mixed methods, model them separately before relying on the tax split.

A whole number from 0 to 20.

Their own figure, including £0.

Why we ask
Enter the known individual ANI, including £0. This also tests the childcare cliff when selected.
Why we ask
Enter your own annual amount at risk; the tool will not assume maximum caps.
Add other income or details

Taxable profit from a trade, profession or partnership.

Rental profit after allowable expenses.

Any other income taxed as non-savings (e.g. pension income, trust income).

Enter what you gave. We gross it up.

Why we ask
Grossed up automatically (÷ 0.8). Lowers your adjusted net income — and the contribution needed.
Why we ask
Use this for a part-year claim, opt-out or entitlement change. Otherwise the tool estimates a full-year award from the number of children.
Partner means spouse, civil partner or cohabiting partner.
Why we ask
Same partner throughout every benefit week. Partner means the claimant’s spouse, civil partner or cohabiting partner.
Only matters if both incomes are exactly equal.

Illustration — worked example

Additional illustrated contribution

£18,000 gross contribution, modelled net cost £7,200

Assumes rest-of-UK rates, a full-year Child Benefit award, no change of partner during the year and no income or Gift Aid beyond what you add.

Your net cost
£7,200
Modelled relief & support
£10,800

60% effective relief. For every £1 it costs you, £2.50 is illustrated as reaching the pension after the modelled tax and benefit effects.

At this ANI, the illustrative earned-income curve is 62%. It assumes the income movement is employment earnings and smooths HICBC across its statutory steps.

Household modelled: 2 children claiming Child Benefit; partner’s adjusted net income as entered in the form.

Current position compared with the illustrated pension-contribution position
PositionAs you are nowWith £18,000 in
Adjusted net income£118,000£100,000
Personal allowance£3,570£12,570
Income tax£38,232£31,032
Employee NI (Class 1 only)£4,370£4,370
Child Benefit kept£0£0
Childcare support£0£0
Net tax and retained-support position£42,602£35,402
Child Benefit clawed backFor information: already taken off Child Benefit kept, so not added to the total.£2,382£2,382

Net tax and retained-support position is income tax plus National Insurance, less the Child Benefit kept and the childcare support. The Child Benefit clawed back, shown below it, is already taken off the Child Benefit kept, so it is not added in.

Figures in this table are rounded down to whole pounds, except the adjusted net income row and any contribution amount in the column heading, which show pence when they have any.

The model includes £10,800 of tax and retained-support effects, alongside a £18,000 pension contribution.
About this calculation

Annual-allowance headroom currently uses the standard £60,000 with no taper, MPAA or carry forward. Confirm the available headroom in the annual allowance calculator before treating the illustrated contribution as feasible.

ITA 2007 s.35 · ITEPA 2003 s.681B–681H

For planning and illustration purposes only. Verify all inputs against source documents. This tool does not constitute financial or tax advice.

Print this quick illustration now. Signed-in users can add a client or file reference before saving it as a PDF. This quick illustration is not available as a saved compliance annex.

Set a target adjusted net income; the tool illustrates the pension contribution that reaches it and shows the modelled tax and support effects side by side.

Free to use, with no sign-up. Your figures stay in this browser unless you choose to share them or send them to your workspace. When you are signed in, downloading this calculator's PDF sends its figures to our servers to build the file. Calculation methods and checks.

— Understanding the result

The “£100k tax trap” is the band of income between £100,000 and £125,140 where the personal allowance is withdrawn at £1 for every £2 earned — an effective marginal rate of 60% for rUK non-savings income (67.5% in Scotland). Above £100,000 you can also fail the income test for Tax-Free Childcare and, in England, working-parent funded hours. A pension contribution can reduce adjusted net income; the tool uses only a childcare amount you enter and does not confirm the other eligibility conditions. It illustrates the result rather than recommending a contribution.

— How it's calculated

Adjusted net income — what counts

Adjusted net income is your total taxable income (salary, bonus, taxable benefits in kind, self-employment, property, dividends and savings) less grossed-up Gift Aid and grossed-up relief-at-source pension contributions. It is the figure that drives the personal-allowance taper, the High Income Child Benefit Charge and the £100,000 childcare cliff — and it is what a pension contribution reduces, £1 for every £1 of gross contribution.

ITA 2007 s.58 (adjusted net income) · s.35 (personal-allowance taper)

The illustrated contribution to the target

From your target adjusted net income the tool solves for the additional gross pension contribution after the existing contribution you enter. It then illustrates the immediate cash cost net of the modelled tax and support effects. Relief at source, net pay and salary sacrifice can produce different tax results where taxable income is low, income is mixed or the contribution exceeds taxable pay. Salary sacrifice can also reduce employee National Insurance, subject to eligible pay, employer scheme rules and the National Minimum Wage floor. The net cost subtracts only the incremental modelled relief and any user-entered childcare support restored by the ANI test.

FA 2004 s.188–192 (pension tax relief) · SSCBA 1992 s.8 (employee NI)

Child benefit and the £100k childcare cliff

From 2024/25, between £60,000 and £80,000 the High Income Child Benefit Charge claws back 1% of Child Benefit for every £200 of adjusted net income above £60,000, rounded down to a whole percentage; at £80,000 the charge percentage reaches 100%, while £60,000 or below removes it. The £100,000 childcare income test is separate. Enter only the annual support genuinely at risk under that test—actual Tax-Free Childcare top-up plus any income-tested working-parent hours value. The tool does not assume maximum caps and does not include universal hours.

ITEPA 2003 s.681B–681H (HICBC) · gov.uk/tax-free-childcare · DfE early-years funding rates

— How to illustrate a pension contribution against the £100k tax trap

  1. Step 1

    Work out your adjusted net income

    Add up your taxable income, then deduct grossed-up Gift Aid and any relief-at-source pension you already pay.

  2. Step 2

    Pick a target

    Choose the adjusted net income you want to reach — £100,000 restores the full personal allowance and can satisfy the childcare income test; £60,000 or below removes post-2024/25 HICBC.

  3. Step 3

    Review the illustrated contribution

    Enter pension contributions already being made. The tool then solves for the additional gross contribution that brings adjusted net income to the target.

  4. Step 4

    See the net cost

    The net cost is the gross contribution less income-tax relief, any NI saving and any child benefit or childcare regained.

  5. Step 5

    Check the annual allowance

    Confirm annual allowance, taper, MPAA, carry-forward, relevant earnings, access and employer feasibility before implementation.

— Worked example

Salary £118,000 · 2 children · relief-at-source · target adjusted net income £100,000 (2025/26, rUK)
Required gross pension contribution
£18,000
What it actually costs you (net)
£7,200
Personal allowance restored
£3,570 → £12,570
Income tax
£38,232 → £31,032
Effective relief on the contribution
60%

Computed live by the same engine the tool above runs. At a £100,000 target the personal allowance is fully restored. HICBC starts to reduce only below £80,000 and is removed at £60,000 or below under the post-2024/25 rules.

— Frequently asked questions

What is the £100k tax trap?

Between £100,000 and £125,140 of adjusted net income, the personal allowance is withdrawn at £1 for every £2 earned. That withdrawal, on top of the 40% higher rate, gives an effective marginal rate of 60% on that band (45% plus the withdrawal gives 67.5% in Scotland). Above £100,000 of adjusted net income, a parent (or their partner) also fails the income test for Tax-Free Childcare and, in England, the working-parent funded hours; the universal hours are unaffected.

What contribution brings adjusted net income to £100,000?

A gross pension contribution reduces adjusted net income £1 for £1. The additional amount is starting adjusted net income after existing contributions minus the target. From £118,000 with no existing contribution to £100,000, for example, the additional gross amount is £18,000.

Is salary sacrifice cheaper than a personal pension?

Not always. Salary sacrifice can reduce employee National Insurance, but the income-tax result can differ from relief at source or net pay where income is mixed, taxable income is low or contributions exceed taxable pay. Employer rules and the National Minimum Wage floor also apply.

Does the Scottish tax trap differ?

Yes. The personal-allowance withdrawal still applies, but on top of the Scottish advanced rate of 45% it produces an effective marginal rate of about 67.5% between £100,000 and £125,140 — open Add other income or details and choose Scottish taxpayer under Income tax regime to see it.

What childcare do I lose over £100,000?

If either parent’s adjusted net income is over £100,000, the household fails the income test for Tax-Free Childcare and, in England, working-parent funded hours. Universal hours are separate, and age, work, residence, provider and account rules still apply. The tool includes only an annual support amount you enter yourself.

— Related