Almost everyone understands the headline rates: 20%, then 40%, then 45%. Almost nobody is told about the band between them where the effective rate is 60%, and it lands on a salary that plenty of people reach.
| Salary | You keep | Per pound |
|---|---|---|
| £30,000 | £720 | 72p |
| £50,000 | £618 | 62p |
| £60,000 | £580 | 58p |
| £99,000 | £580 | 58p |
| £100,000 | £380 | 38p |
| £110,000 | £380 | 38p |
| £125,000 | £509 | 51p |
| £150,000 | £530 | 53p |
Why £100,000 is the cliff
The personal allowance — the first £12,570 you earn tax-free — starts disappearing once you earn over £100,000. It goes at £1 of allowance for every £2 of income. So each extra pound is taxed at 40%, and destroys 50p of tax-free allowance, which is itself then taxed at 40%. Add National Insurance at 2% and the effective rate on that pound is 62%.
The band runs from £100,000 to £125,140, at which point the allowance has gone entirely and the rate falls back to 47%. That is the strange part: earning more makes your marginal rate go down.
What the whole band costs
Going from £100,000 to £125,140 is a gross rise of £25,140. Your take-home goes from £68,557 to £78,111 — an increase of £9,553. You did over £25,000 of extra work for under £10,000.
What people actually do about it
The standard move is to take the money as a pension contribution instead. Pension contributions reduce your adjusted net income, and if they bring you back under £100,000 the allowance is restored. Inside the band, every £1,000 sacrificed effectively costs you £380 of take-home, because £380 is all you were going to see of it.
Salary sacrifice goes further, because it also removes the National Insurance. This is not advice, and whether it suits you depends on your age, your other income and what you need the money for — but it is why the band exists as a topic of conversation at all.
Run your own figure on the take-home calculator: the marginal rate is shown next to the result, and it turns red inside the trap.