Pension Salary Sacrifice Explained
Salary sacrifice for pension contributions is one of the most tax-efficient arrangements available to UK employees. By agreeing to reduce your contractual salary in exchange for increased employer pension contributions, you save both income tax and National Insurance — rather than just income tax through the standard "relief at source" method. This guide explains how salary sacrifice works, who benefits, and what to watch out for.
How Salary Sacrifice Works
Under a salary sacrifice arrangement:
- You agree with your employer to reduce your gross salary by the amount of your pension contribution.
- Your employer pays the sacrificed amount directly into your pension scheme as an employer contribution.
- Your reduced salary is used as the basis for calculating income tax and National Insurance.
- Because your gross pay is lower, you pay less tax and NI.
The key difference from relief at source: with salary sacrifice, the money never counts as your earnings at all. With relief at source, it counts as your earnings first (you pay NI on it) and the pension deduction happens after tax.
Tax Savings: Salary Sacrifice vs Relief at Source
Here's a direct comparison for a 5% pension contribution at different salary levels:
| Salary | Contribution | Tax Saved (Both Methods) | NI Saved (Sacrifice Only) | Total Extra Saving |
|---|---|---|---|---|
| £25,000 | £1,250 | £250 | £100 | £100/year |
| £35,000 | £1,750 | £350 | £140 | £140/year |
| £50,000 | £2,500 | £500 | £200 | £200/year |
| £60,000 | £3,000 | £1,200* | £60 | £60/year |
| £105,000 | £5,250 | £3,150* | £105 | £3,150/year* |
*At £60,000, the contribution spans basic and higher rate bands. At £105,000, the contribution triggers the personal allowance restoration, making the tax saving much larger.
The £100,000 Strategy
Salary sacrifice becomes exceptionally powerful for earners between £100,000 and £125,140. In this range, the personal allowance taper creates an effective 60% marginal tax rate (plus 2% NI = 62%). Sacrificing enough salary to drop below £100,000 saves tax at this 62% rate.
Example: earning £112,000 and sacrificing £12,000 into your pension:
| Gross salary | £112,000 |
| Sacrifice | £12,000 |
| New gross | £100,000 |
| Personal allowance restored | £12,570 (was £6,570) |
| Income tax saving | ~£7,200 |
| NI saving | £240 |
| Lost take-home pay | ~£4,560 |
| Amount into pension | £12,000 |
| Effective cost per £1 of pension | 38p |
For every £1 you put into your pension, you only lose 38p of take-home pay. This is the single most tax-efficient arrangement in the UK tax system for employees in this income range.
Employer NI Savings
Your employer also saves NI on the sacrificed amount — 15% in 2026/27. On a £3,000 sacrifice, the employer saves £450. Some employers pass this saving to you as an additional pension contribution, while others keep it. Check your scheme documentation or ask your HR department.
If your employer passes the saving through, your pension contribution is effectively more than 5% of your original salary — the employer NI saving adds an extra 15% boost. On a £50,000 salary with 5% sacrifice (£2,500), the employer could add their £375 NI saving, bringing the total pension contribution to £2,875.
Considerations and Drawbacks
Impact on Mortgage Applications
With salary sacrifice, your P60 and payslip show the reduced salary. A £50,000 salary with 10% sacrifice shows as £45,000 on your P60. Most mortgage lenders will use this lower figure:
- At 4.5x income multiple, a £50,000 salary gives a maximum mortgage of £225,000.
- With 10% sacrifice showing £45,000, the maximum drops to £202,500 — a £22,500 reduction.
- Some lenders will "add back" pension sacrifice if you provide a letter from your employer, but not all.
If you're planning to apply for a mortgage, discuss this with your broker before increasing your sacrifice.
Impact on Other Benefits
Salary sacrifice can affect benefits calculated on your gross salary:
- Life insurance: Often a multiple of salary. If calculated on post-sacrifice salary, your cover decreases.
- Statutory pay: Statutory Sick Pay, Maternity Pay, and Paternity Pay are based on your actual (post-sacrifice) earnings. If sacrifice reduces your pay below the qualifying threshold, you could lose entitlement.
- Redundancy pay: Statutory redundancy is based on your actual salary, which may be the post-sacrifice amount.
- Salary cannot go below minimum wage: Salary sacrifice cannot reduce your pay below National Minimum Wage.
Flexibility
Salary sacrifice is a contractual arrangement — you can't simply change it month to month. Most schemes allow changes once or twice per year (typically at the annual review), or upon a "life event" (marriage, birth of a child, house purchase). This makes it less flexible than relief at source, where you can vary your contributions freely.
Who Should Use Salary Sacrifice?
- Basic rate taxpayers (£12,570 – £50,270): Save 8% NI on every pound sacrificed. Worth doing for the NI saving alone.
- Higher rate taxpayers (£50,270 – £100,000): Save 2% NI. The saving is smaller, but still free money.
- Earners £100,000 – £125,140: Potentially enormous savings due to the personal allowance taper. This is the most tax-efficient use of salary sacrifice.
- Anyone whose employer passes through employer NI savings: Additional free pension contributions.
Who Should Avoid Salary Sacrifice?
- Low earners near minimum wage: If sacrifice would take your pay below minimum wage, it's not allowed.
- People about to apply for a mortgage: The reduced P60 salary could limit borrowing capacity.
- Pregnant employees: If sacrifice reduces your salary below the SMP qualifying threshold, you could receive less maternity pay.
Calculators
- Pension Contribution Calculator — Compare sacrifice vs relief at source
- Salary Calculator — See pension impact on take-home pay
- Take-Home Pay Calculator — Full breakdown with pension