Salary sacrifice is the only pension arrangement that saves National Insurance as well as income tax. That is worth real money now — and it is being capped from April 2029.
How it works
You agree with your employer to give up part of your contractual salary in exchange for a pension contribution. The key word is contractual: the money is never paid to you as earnings, so it is not there to be taxed. Both income tax and National Insurance are calculated on the reduced figure.
Your employer also saves their 15% National Insurance on the sacrificed amount. Many pass some or all of that saving into your pension too, which makes a well-run scheme better than it first appears. It is always worth asking whether yours does.
The three arrangements compared
On a £50,000 salary with a £5,000 contribution, 2026/27 rates:
| Arrangement | Income tax | National Insurance | Cost to you | Take-home pay |
|---|---|---|---|---|
| Salary sacrifice | £6,486 | £2,594 | £5,000 | £35,920 |
| Net pay | £6,486 | £2,994 | £5,000 | £35,520 |
| Relief at source | £7,486 | £2,994 | £4,000 | £35,520 |
Net pay and relief at source produce identical take-home pay for a basic rate taxpayer — the difference is only in when the relief arrives. Salary sacrifice leaves you £400 better off, which is exactly 8% of £5,000: the employee National Insurance you did not pay.
Above the upper earnings limit of £50,270 the National Insurance rate drops to 2%, so the sacrifice advantage shrinks to 2% of the contribution for higher earners. It is most valuable to people earning between £12,570 and £50,270.
The other advantages
- It reduces student loan repayments. Sacrifice lowers the earnings figure used for student loan deductions; the other two arrangements do not. On a Plan 2 loan that is a further 9% of the sacrificed amount.
- It escapes the £100,000 trap efficiently. Sacrificing enough to bring adjusted net income to £100,000 restores the personal allowance — and the childcare support that is lost above it. More on the trap.
- Higher rate relief is automatic. Unlike relief at source, there is nothing to claim from HMRC.
The catches
- You cannot sacrifice below the National Minimum Wage. This is a hard legal floor and it limits how much lower earners can put in.
- Your official salary is lower. That can affect mortgage applications, though most lenders will work from the pre-sacrifice figure if you ask and provide a letter.
- Salary-linked benefits fall. Statutory maternity pay, death-in-service cover, and redundancy pay are often based on the reduced salary. Good schemes protect these ("notional salary"); check yours.
- It is a contract change. You cannot switch it on and off freely — usually only at set points or on a life event.
The £2,000 cap from April 2029
The Autumn Budget of 26 November 2025 announced that National Insurance relief on salary-sacrificed pension contributions will be capped at £2,000 a year from April 2029. Above that, the sacrificed amount will still escape income tax but will attract employee and employer National Insurance at the normal rates.
It does not affect 2026/27, so nothing changes yet. But if you sacrifice more than £2,000 a year — which is most people contributing 5% or more of a middling salary — the arrangement will become less valuable, and the gap between sacrifice and net pay will narrow to almost nothing for the excess.
Three years is enough notice to plan. The sensible reading is that the income tax relief, which is by far the larger part, is untouched — so the case for contributing at all is unchanged.
Which one am I on?
Look at your payslip. Under salary sacrifice your gross pay is already reduced and there is no separate pension line, or a line showing an employer contribution only. Under net pay you will see your full gross with a pension deduction before tax. Under relief at source the deduction comes after tax and is 80% of the headline percentage. If it is not obvious, payroll will tell you — and it is worth knowing, because it changes what your contribution actually costs you.