Guide · tax year 2026/27
Pension salary sacrifice: how it works
Swap a slice of salary for a pension contribution and the tax and National Insurance on that slice simply never happen. Here is the mechanism, the savings and the small print.
The mechanics
Salary sacrifice is a change to your employment contract. You agree to reduce your gross salary by a set amount, and in exchange your employer pays that amount into your pension as an employer contribution. On paper you earn less; in practice the money still ends up yours, just inside the pension instead of the payslip.
The tax logic follows from that. Income tax and National Insurance are charged on pay you receive. The sacrificed slice is never pay, so neither charge ever arises. There is no relief to claim and no form to fill in: the saving is automatic, every payday.
This is different from paying into a pension from your bank account. A personal contribution gets income tax relief, but the National Insurance has already been deducted by then and is not refundable. Sacrifice is the only common route that avoids the NI as well.
What you save
On every pound sacrificed you save income tax at your marginal rate plus the employee NI that pound would have carried: 8% between £12,570 and £50,270, 2% above. A worked example, using the same figures as our calculator:
£40,000 salary, £2,000 sacrificed, 2026/27
- Into the pension£2,000.00
- Income tax saved at 20%£400.00
- Employee NI saved at 8%£160.00
- True cost in take-home pay£1,440.00
£2,000 in the pension for £1,440 out of pocket: 28p of every pound came straight off the tax bill. A higher rate earner does better still, saving 40% tax plus 2% NI, so the same £2,000 would cost £1,160. Try your own numbers in the salary sacrifice calculator, which splits a sacrifice correctly when it straddles the £50,270 threshold.
What your employer saves, and the pass-on question
Employers pay 15% National Insurance on salaries above £5,000. Every pound you sacrifice is a pound they no longer pay it on, so a £2,000 sacrifice saves your employer £300 a year. Nothing obliges them to share that.
In practice, policies vary. Some employers add their full NI saving to your pension, some add part, and many keep it as a quiet payroll saving. It costs one email to payroll to find out which kind yours is, and the difference compounds: £300 a year invested over a working life is a serious sum. If your employer does pass it on, the calculator has a toggle that adds it to the pension figure.
Watch-outs before you sign
The minimum wage floor. Your contractual pay after the sacrifice must stay at or above the National Minimum Wage. Employers are required to refuse an arrangement that would breach it, so lower earners hit a hard cap on how much they can sacrifice.
Lenders see the lower salary. Mortgage affordability checks work from your reduced contractual pay. Some lenders will take the sacrifice into account if you explain it, many will not. If a mortgage application is coming up, consider the timing before raising the sacrifice.
Statutory pay references. Statutory maternity, paternity, adoption and sick pay are calculated from the post-sacrifice salary, and some death-in-service benefits reference it too. A big sacrifice shortly before parental leave can cost real money.
It locks for a while. Because it amends your contract, a sacrifice usually stays fixed for a set period or until a life event. It is not a dial you can turn month to month the way a personal contribution is.
Common questions
What is pension salary sacrifice in simple terms?
You agree to a contractual pay cut, and your employer pays the same amount into your pension as an employer contribution. Because that slice of pay never reaches you, it carries no income tax and no National Insurance. The full amount lands in the pension while your take-home pay falls by much less.
How much does salary sacrifice actually save?
Income tax at your marginal rate plus employee NI on the sacrificed slice: 20% tax and 8% NI for most basic rate earners, 40% tax and 2% NI above £50,270. So £1,000 sacrificed costs a basic rate earner £720 in take-home pay and a higher rate earner £580.
Is salary sacrifice better than paying into my pension myself?
Usually, yes. A personal contribution gets the income tax back through tax relief, but the National Insurance is already gone by the time the money reaches your bank account. Sacrifice skips the NI at source: 8% or 2% extra saving on every pound, plus whatever share of the 15% employer NI saving your employer chooses to pass on.
Can I sacrifice as much salary as I like?
Two limits apply. Your pay after the sacrifice cannot fall below the National Minimum Wage, which is the hard floor for lower earners. And pension contributions from all sources are capped by the £60,000 annual allowance for most people, lower for very high earners or after flexibly accessing a pension.
Does salary sacrifice reduce my state pension?
Almost never. You keep building state pension entitlement as long as your reduced salary stays above the lower earnings limit, which sits well below full-time minimum wage pay. Only a very large sacrifice on a very small salary could touch it, and the minimum wage floor usually prevents that anyway.
Ready for your own figures? The salary sacrifice calculator shows the tax and NI saved on any salary and sacrifice. And if you also take dividends, sacrificing salary frees up basic rate band, which the dividend tax calculator can turn into a second saving.