What is salary sacrifice? (And why the name is wrong)

Start with the name, because it's putting people off

"Salary sacrifice" sounds like something you lose. It isn't. You're swapping part of your cash pay for a pension contribution of the same size, and paying less tax and National Insurance in the process. Plenty of employers already call it salary exchange, which is a much better description of what actually happens — nothing is being sacrificed, it's a swap. If your offer letter or benefits handbook uses the word sacrifice, read it as "exchange" and it'll make far more sense.

How it actually works

Normally you're paid your salary, tax and National Insurance come off, and your pension contribution is deducted after that. With salary exchange, the order changes: your contractual salary is reduced first, and your employer pays that amount straight into your pension as an employer contribution. Because your gross salary is now lower, there's less of it for tax and NI to be charged on. Say you earn £30,000 and exchange 5% — £1,500. Your contractual salary becomes £28,500, and your employer pays £1,500 into your pension on top of whatever they already contribute. The same money ends up in your pension; you just paid less tax getting it there.

What you actually save

For a basic-rate taxpayer, employee National Insurance is charged at 8% on earnings between £12,570 and £50,270, and 2% above that. Exchange £1,000 of salary and you avoid the 20% income tax and the 8% NI on it, so roughly £280 more of every £1,000 ends up working for you rather than going to HMRC. Higher-rate taxpayers save 40% plus 2%. There's a second saving that's easy to miss: your employer pays National Insurance at 15% on earnings above £5,000, and they don't pay it on exchanged salary either. Many employers pass some or all of that saving into your pension too — so it's worth asking whether yours does, because it can add meaningfully to the total.

The catches worth knowing about

Because salary exchange genuinely reduces your gross salary, anything calculated from gross salary can be affected. That includes mortgage borrowing power, statutory maternity pay and statutory sick pay. For most people the arrangement is still clearly worth it, but if you're about to apply for a mortgage or planning a family, check the timing before you commit. Two other things: some employers calculate their own pension contribution on your post-exchange salary rather than your original one, which quietly reduces what they put in — ask which they use. And your salary can't be exchanged below the National Minimum Wage, so there's a floor on how much you can do.

What's changing in 2029

This is worth knowing now even though it's a few years off. From 6 April 2029, only the first £2,000 exchanged each year will be exempt from National Insurance — anything above that will have employee and employer NI charged on it. Income tax relief on pension contributions continues as normal. HMRC estimates around 7.7 million UK employees currently use salary exchange for their pension, and that roughly 44% of them exchange more than £2,000 a year, so a little under half would be affected. The current rules stay in place for the 2026/27, 2027/28 and 2028/29 tax years. For most early-career readers exchanging a few percent of a starting salary, the £2,000 threshold will cover you entirely.

What to check in a job offer

If an employer offers salary exchange for pension contributions, that's a point in their favour — it means more of your money reaches your pension. Ask three things: whether they pass on their own National Insurance saving, whether their pension contribution is based on your pre-exchange or post-exchange salary, and whether the arrangement is opt-in or automatic. The answers tell you how generously the scheme has been designed.

How OfferWise treats it

OfferWise scores the employer and employee pension percentages you enter, so the value of a strong pension shows up in your offer score regardless of how the contributions are structured. Salary exchange changes how efficiently the money gets there rather than how much goes in — so enter the percentages your offer letter states and the score reflects the package properly.

Comparing job offers? OfferWise scores salary, pension, benefits and your commute in one number — free.