How Pension Salary Sacrifice Works (And Why It's Worth Doing)
Salary sacrifice is one of the most tax-efficient ways to save for retirement. By restructuring how your pension contributions are paid, you can save hundreds of pounds in tax and National Insurance every year, and your employer might save too.
What is salary sacrifice?
Salary sacrifice (also called salary exchange) is an arrangement where you formally agree to reduce your gross salary in exchange for a non-cash benefit, most commonly employer pension contributions.
Instead of you paying £200/month into your pension from your take-home pay, your employer pays it directly, and your salary is reduced by £200 first. The result: you never pay income tax or National Insurance on that £200, rather than just getting tax relief on it after the fact.
It's not a pension top-up. Your pension gets the same amount either way. The saving comes purely from the order of deductions.
Why salary sacrifice saves more than standard pension relief
When you pay into a pension normally, HMRC gives you income tax relief but not National Insurance relief. Salary sacrifice gives you both. Here's the comparison for a basic-rate taxpayer:
| Standard relief | Salary sacrifice | |
|---|---|---|
| Gross contribution | £2,400/year | £2,400/year |
| Income tax relief (20%) | ✓ £480 saved | ✓ £480 saved |
| Employee NI relief (8%) | ✗ Not available | ✓ £192 saved |
| Total annual saving | £480 | £672 |
| Real cost of £2,400 pension | £1,920 | £1,728 |
Based on a basic-rate (20%) taxpayer with salary between £12,570 and £50,270 in 2026/27. Employee NI rate 8% on earnings between £12,570 and £50,270.
The savings are even bigger for higher earners
Higher-rate taxpayers save 40% income tax plus 2% NI (on earnings above £50,270) via salary sacrifice. For every £1,000 of pension contribution:
Basic-rate taxpayer
Salary £20,000–£50,270
£280
saved per £1,000 contributed
(20% tax + 8% NI = 28%)
Higher-rate taxpayer
Salary £50,271+
£420
saved per £1,000 contributed
(40% tax + 2% NI = 42%)
Your employer saves too (and may pass it on)
When your salary decreases, your employer pays less employer National Insurance (13.8% on earnings above £5,000). On a £2,400 contribution, they save around £331/year.
Some employers pass this NI saving back to employees, either as an enhanced pension contribution or as a pay supplement. Ask your HR or payroll team whether your employer has a policy on this. A few hundred pounds extra into your pension each year can make a significant difference over a career.
Things to watch out for
Mortgage affordability
Lenders assess affordability based on your contracted salary. A large salary sacrifice reduces your declared income, which can lower the amount you can borrow. If you're planning to apply for a mortgage soon, factor this in.
Maternity, paternity, and sick pay
Statutory maternity and paternity pay are calculated on your contracted (sacrificed) salary. If your pay drops below the lower earnings limit (£6,396 in 2026/27), this can reduce your entitlement. Some employers protect your pre-sacrifice salary for these calculations, so check your contract.
State Pension and NI credits
If salary sacrifice pushes your income below the lower earnings limit (£6,396/year), you may stop accruing qualifying years for the State Pension. Most employees earning a full-time salary are nowhere near this level, but check if you work part-time or close to the threshold.
Annual allowance
Total pension contributions (employer + employee + any salary sacrifice) must not exceed the annual allowance of £60,000 in 2026/27, or your annual earnings if lower. If you're a high earner, the tapered allowance reduces this. Exceeding the allowance triggers a tax charge.
How to set up salary sacrifice
Salary sacrifice must be formally agreed with your employer. You can't unilaterally change your pay arrangements. Here's the typical process:
- 1
Check your employer offers it
Ask your HR or payroll team. Many employers with workplace pensions (especially defined contribution schemes) offer it automatically, but some don't.
- 2
Agree a new contract / side letter
The arrangement requires a formal change to your employment contract. Your employer should provide a letter confirming your new contractual salary and the enhanced pension contribution amount.
- 3
Payroll makes the change
Your payslip will show a reduced gross salary and a larger employer pension contribution. The pension provider receives the same total amount either way.
- 4
Ask about the employer NI saving
When arranging the sacrifice, ask whether your employer passes back any of their NI saving. This is good practice and some larger employers do it as standard.