£100k tax trap calculator
See the personal allowance you lose over £100,000, your tax and NI rate on the next £1,000, and the pension contribution that brings you back to £100,000.
- Tax and NI on your next £1,000
- 62%
- £620 of it: £600 income tax and £20 National Insurance
- Personal allowance left
- £7,570
- of £12,570, with adjusted net income of £110,000
- Extra tax from the taper
- £2,000
- on £5,000 of lost allowance
Your adjusted net income is £110,000, so you’ve lost £5,000 of the personal allowance.
Paying £10,000 more into a pension brings adjusted net income back to £100,000
By salary sacrifice
- Cost to your take-home
- £3,800.08
- Tax relief
- £6,000
- NI saved
- £199.92
That’s more than your salary after the pension you already sacrifice, so it can’t all go this way.
By relief at source
- Cost to your take-home
- £4,000
- You pay in
- £8,000
- Provider adds
- £2,000
- You claim back from HMRC
- £4,000
Salary sacrifice takes the money from your pay before tax and National Insurance, so all the relief arrives straight away and you save National Insurance too. With relief at source you pay from take-home, the provider adds 20%, and you claim the rest through a tax return or by asking HMRC to change your tax code.
That takes your pension savings this year past the £60,000 annual allowance, before counting your employer’s contributions. You may be able to carry forward unused allowance from the last three years; otherwise there’s a tax charge on the excess.
With adjusted net income over £100,000, your family can’t get Tax-Free Childcare or, in England, the 30 hours of funded childcare for working parents. That applies if either parent is over. Getting back to £100,000 keeps them open, if you meet the other conditions.
Show the rates by salary
| Salary | Tax and NI on each extra pound |
|---|---|
| £40,000 to £50,270 | 28% |
| £50,271 to £100,000 | 42% |
| £100,001 to £125,140 | 62% |
| £125,141 and over | 47% |
Uses the 2026 to 2027 rules. The personal allowance of £12,570 falls by £1 for every £2 of adjusted net income over £100,000 and is gone at £125,140. Adjusted net income is your taxable income less pension contributions (relief at source ones grossed up by 25%) and Gift Aid. Rates are Scottish or UK income tax plus employee National Insurance, worked out monthly; student loan repayments would add 9% or 6% more. Other income is taxed like salary with no NI, so savings interest and dividends, which have their own allowances and rates, aren’t covered. This is general, not about your situation.
What goes in
Your salary, any other taxable income such as rental profit, and the pension contributions you already make. Pension taken from your pay before tax, by salary sacrifice or net pay, goes in the pension before tax box. For a relief at source pension, put in what you pay and the calculator adds the 25% top-up. Answer yes to living in Scotland if you pay Scottish income tax.
Why the rate reaches 60%
Once your adjusted net income passes £100,000, the £12,570 personal allowance falls by £1 for every £2 until it’s gone at £125,140. Each extra £1,000 in that range is taxed at 40% and also takes £500 of allowance, which is then taxed at 40% too. That’s £600, or 60%. Add 2% National Insurance and it’s 62%. In Scotland the advanced rate is 45%, so the same range costs 67.5%, or 69.5% with NI.
On a £110,000 salary you keep £7,570 of the allowance and pay £2,000 more tax than you would with all of it.
Getting back to £100,000
Pension contributions come off adjusted net income. On £110,000, another £10,000 into a pension costs about £3,800 of take-home by salary sacrifice, because none of it is taxed and you skip the 2% NI. By relief at source you pay £8,000, the provider adds £2,000 and you claim £4,000 back from HMRC, so it costs £4,000.
It matters for childcare too. Your family can’t get Tax-Free Childcare, worth up to £2,000 a year for each child, or the 30 hours of funded childcare for working parents in England, if either parent expects adjusted net income over £100,000.
Sources
- Income Tax rates and Personal Allowances, GOV.UK
- Adjusted net income, HMRC
- Rates and thresholds for employers 2026 to 2027, HMRC
- Scottish income tax rates and bands 2026 to 2027, Scottish Government
- Scottish Rate Resolution 2026 to 2027 (S6M-20844), agreed 19 February 2026, Scottish Parliament
- Tax on your private pension contributions, GOV.UK
- Tax-Free Childcare, GOV.UK
- 30 hours free childcare for working parents, GOV.UK