Salary sacrifice into a pension: the catch-free pay rise most people miss

Salary sacrifice is one of the few genuinely free upgrades sitting in most workplace pension schemes, and a surprising number of people never opt in because nobody explained what it actually does to a payslip.

The idea is simple once you see it laid out. You agree to give up part of your salary. In exchange, your employer pays that same amount straight into your pension as an employer contribution instead. Your gross pay drops, so does the tax and National Insurance calculated on it, and the pension gets the money that would otherwise have gone to HMRC.

What actually happens to your payslip

Say you earn £35,000 a year and decide to sacrifice £2,000 into your pension, on top of whatever you already contribute. Without sacrifice, a normal employee pension contribution of £2,000 comes out of your take-home pay after tax and National Insurance have already been deducted, then the pension provider adds basic rate tax relief on top.

With salary sacrifice, your employer treats you as earning £33,000 instead of £35,000, and simply pays £2,000 extra into the pension directly. Because that £2,000 was never paid to you as salary, you never pay Income Tax or employee National Insurance on it. At current rates that is 20% Income Tax plus 8% employee National Insurance, so 28% combined for a basic rate taxpayer.

You have £1,440 less in your pocket over the year, in exchange for £2,000 landing in your pension. That £560 difference is money that would otherwise have gone to HMRC, and it never touches your bank account long enough to be taxed at all.

The bit most people never hear about: employer NI

Here is the part that makes salary sacrifice better than an ordinary pension contribution, not just equal to one. Employers pay National Insurance too, currently 15% on top of your salary. When your pay drops by £2,000 through sacrifice, your employer's NI bill falls by £300 that year, because that £2,000 no longer counts as salary for them either.

Some employers keep that £300 as a saving for the business. A good number, especially larger ones with a well-run scheme, pass some or all of it back into your pension on top of your own sacrifice. Ask your HR team or scheme documentation which camp your employer falls into, because it is a genuine question worth asking rather than assuming the answer is no. Over a career, an extra £300 a year compounding inside a pension is not trivial.

Where it can bite

None of this is a free lunch in every circumstance, and there are a handful of situations worth checking before you increase a sacrifice arrangement.

• Minimum wage. Your notional pay after sacrifice cannot fall below the National Minimum or Living Wage. Employers are required to cap the sacrifice automatically if it would, so this mostly affects lower earners with a large sacrifice request.
• Mortgage applications. Lenders usually work from your payslip, and a lower salary figure occasionally means a slightly lower amount they will offer. If you are about to apply for a mortgage, it is worth checking with a broker first rather than discovering it during the application.
• Statutory pay. Statutory Maternity, Paternity, and Sick Pay are often calculated from average earnings over a reference period, so a lower headline salary can, in some cases, reduce them. HR should be able to tell you whether your scheme accounts for this around leave.
• The Lower Earnings Limit. Drop your gross pay below this threshold and the year may stop counting towards your State Pension. This is a real risk for lower earners and one reason many schemes will not let sacrifice take pay below it.

For most people on an average salary sacrificing a moderate amount, none of these apply, and the arrangement is close to strictly better than an ordinary contribution. But "close to strictly better" is not the same as "always better for everyone," which is why the list above is worth five minutes of your attention rather than none.

One thing worth doing before you sign up

Check whether your employer's scheme lets you dial the sacrifice up or down easily, and how often. Life changes, and a £2,000 sacrifice that suited your budget this year might feel tight next year if your outgoings rise. Some employers only allow changes once a year outside of specific life events like having a baby or getting a new job, so the flexibility, or lack of it, is worth knowing about up front rather than discovering when you want to adjust it.

It is also worth checking the sacrifice does not push you past your pension annual allowance, since the tax relief advantage disappears once contributions exceed it. Most people on typical salaries are nowhere near this limit, but higher earners with generous employer contributions on top should have their scheme check the sums.

This guide is general information, not financial advice. Figures are illustrative and based on 2026/27 rates; check your own payslip and scheme rules before changing your pension contributions.