How Salary Sacrifice for Pensions Cuts Your National Insurance Bill Today

Salary sacrifice for pensions is one of the few genuinely free upgrades available to most UK employees right now — and plenty of people who have access to it either aren’t using it or don’t understand why it’s worth doing. Here’s how the saving actually works today, in the 2026/27 tax year, before any of the changes coming later this decade.

The basic mechanism

Normally, you pay pension contributions out of your salary after National Insurance has already been calculated on it. With salary sacrifice, you agree to a contractual reduction in your gross salary, and your employer pays the sacrificed amount into your pension directly as an employer contribution instead.

Because your official salary is lower, both you and your employer pay less National Insurance — on top of the income tax relief you’d get on a pension contribution anyway.

A worked example

Take someone earning £28,000 a year who contributes 5% of salary to their pension (£1,400), with a 3% employer contribution (£840).

• Without salary sacrifice: Employee and employer NICs are both calculated on the full £28,000 salary. The employee still gets income tax relief on their £1,400 contribution, but pays NICs as if that money were still in their pay packet.
• With salary sacrifice: The employee’s gross salary is treated as £26,600 (£28,000 minus the £1,400 sacrificed), so both employee and employer NICs are calculated on the lower figure. The employer’s total pension contribution becomes £2,240 (their £840 plus the £1,400 sacrificed amount), and the employee’s take-home NIC bill falls too.

The exact saving depends on your NIC rate: employees currently pay Class 1 NICs at 8% on earnings between the primary threshold (£12,570 for 2026/27) and the upper earnings limit (£50,270), and 2% above that. Employers pay 15% on earnings above the £5,000 secondary threshold for 2026/27.

What you can do with the saving

Most payroll schemes let you choose:

• Boost your take-home pay — keep the NI saving as extra cash each month.
• Boost your pension — redirect the NI saving straight back into your pension pot, so you retire with more without your take-home pay changing at all. Many people don’t realise this option exists, and it’s often the better default choice.

Things to check before you sign up

• Minimum wage protection. Your employer must ensure your post-sacrifice salary doesn’t fall below the National Living Wage or National Minimum Wage. This mainly affects lower earners and part-time workers, who may not be able to sacrifice as much as they’d like.
• Effect on means-tested benefits and thresholds. A lower official salary from salary sacrifice can affect things like mortgage affordability assessments, Statutory Maternity/Paternity Pay calculations, and eligibility for income-linked benefits. It can also help you fall under thresholds for the High Income Child Benefit Charge or Tax-Free Childcare eligibility — usually a benefit, but worth understanding either way.
• It’s a contractual change, not a one-off election. You’ll sign a variation to your employment contract, and most employers only allow changes at set points in the year (for example, once annually or after a life event).

A change on the horizon, not yet in effect

From 6 April 2029, the NI exemption on salary-sacrificed pension contributions will be capped at £2,000 a year, with NICs applying above that threshold — we cover exactly how the new cap will work here. That’s still years away and doesn’t affect the saving described here for the 2026/27 tax year — if anything, it’s a reason to make full use of salary sacrifice now while there’s no cap on the NI-free amount.

The bottom line

If your employer offers salary sacrifice and you’re not using it, you’re very likely leaving free money on the table — either in your pay packet or, better, in your pension. Check with your payroll or HR team what’s on offer, and consider directing the NI saving straight into your pension rather than your take-home pay.