Salary sacrifice is the single biggest no-cost win in UK personal finance—a way of paying into your pension that saves both income tax and National Insurance, often with the employer’s NI saving partially returned to you on top. For higher-rate taxpayers it can take the net cost of £100 in the pension below £55.
This article explains exactly how it works, with worked numbers across pay grades, and the specific situations where sacrifice does not make sense in spite of the headline maths.
The mechanics
A normal pension contribution from take-home pay:
- You earn £100 of gross salary.
- Income tax (20%) and employee NI (8%) are deducted: take-home £72.
- You contribute £72 to your pension.
- The pension provider claims back 20% basic-rate tax → £90 in the pension.
- Higher-rate taxpayers reclaim a further £20 via Self Assessment → net cost £55 for £100 in the pension.
A salary sacrifice contribution:
- You agree with your employer to give up £100 of gross salary.
- Your employer pays £100 directly into your pension.
- You don’t pay income tax or employee NI on the £100.
- Your employer doesn’t pay employer NI on the £100 either.
- Net cost to you: take-home reduces by £72 (income tax + employee NI saved), but £100 lands in the pension.
Salary sacrifice is straight saving of:
- 20% income tax (basic rate) → 40% (higher) → 45% (additional rate).
- 8% employee NI (between primary threshold and upper earnings limit) → 2% above.
Plus, often, a share of the employer’s saved NI.
How much you save by income band
For 2026/27 with NI bands as in force.
Basic-rate taxpayer (£12,570 – £50,270)
- Income tax saved: 20%.
- Employee NI saved: 8%.
- Total saved: 28% of the contributed amount.
- Net cost of £100 in pension: £72.
Higher-rate taxpayer (£50,270 – £125,140)
- Income tax saved: 40%.
- Employee NI saved: 2% (above UEL £50,270).
- Total saved: 42% of the contributed amount.
- Net cost of £100 in pension: £58.
Additional-rate taxpayer (over £125,140)
- Income tax saved: 45%.
- Employee NI saved: 2%.
- Total saved: 47% of the contributed amount.
- Net cost of £100 in pension: £53.
The £100k–£125k personal allowance trap
For income between £100,000 and £125,140, your personal allowance is reduced by £1 for every £2 earned. The effective marginal tax rate in this band is 60%. Salary sacrifice is uniquely powerful here:
- Reduce earnings from £125,000 to £100,000 by sacrificing £25,000.
- Save £15,000 in income tax (60% effective).
- Save £500 in employee NI (2% above UEL).
- Total saving: £15,500 for £25,000 in pension.
- Net cost: £9,500 for £25,000 in the pension.
For people in this band, sacrificing as much as possible to drop below £100k is one of the highest-return moves in UK personal finance—and one of the most consistently missed.
Employer NI pass-through
When you sacrifice salary, your employer also saves on Employer National Insurance—currently 15% for 2026 (up from 13.8% pre-2025).
Some employers pass this saving back to the employee:
- Full pass-through—the employer pays the saved 15% into your pension on top.
- Partial pass-through—e.g. 50% of the saving goes to you.
- No pass-through—the employer keeps the saving.
A £100 sacrifice with full pass-through becomes £115 in the pension on a net cost of £72 (basic) or £58 (higher rate). Net cost of £115 in pension:
- Basic rate with full pass-through: ~£63.
- Higher rate with full pass-through: ~£50.
If your employer does not currently offer pass-through, it is worth asking. They have nothing to lose—the saving is the employee’s contribution, not theirs.
Worked example: a £60,000 earner
Someone earning £60,000 sacrificing 10% of salary (£6,000) into their pension.
Without sacrifice:
| Line | Amount |
|---|---|
| Gross salary | £60,000 |
| Income tax | -£11,432 |
| Employee NI | -£3,222 |
| Take-home | £45,346 |
With sacrifice (£6,000 → pension):
| Line | Amount |
|---|---|
| Adjusted gross | £54,000 |
| Income tax | -£9,032 |
| Employee NI | -£3,102 |
| Take-home | £41,866 |
Take-home dropped by £3,480, but £6,000 went into the pension. Net cost: £3,480 for £6,000 in the pension—a 42% saving.
If the employer passes through their 15% NI saving (£900), £6,900 lands in the pension for the same £3,480 cost.
When salary sacrifice doesn’t make sense
Several specific cases.
Your earnings are at or below the personal allowance
If you earn under £12,570, you do not pay income tax. You do pay employee NI between £12,570 and £50,270. Salary sacrifice still saves the 8% NI, but the total saving is small.
You’re applying for a mortgage soon
Lenders use your reduced gross salary for affordability assessments. Some uplift documented salary sacrifice; many do not. Sacrificing 5% of salary can reduce your borrowing capacity by 5%.
If you are applying within the next six months, hold off on increasing sacrifice—or ask your lender directly whether they uplift.
Your sacrifice would push pay below the National Minimum Wage
It is illegal for an employer to pay below NMW. If you are already close to the threshold, salary sacrifice may be capped.
Maternity, paternity, or sick pay calculations
Statutory maternity pay (SMP), shared parental pay, and SSP are calculated on post-sacrifice earnings. A sustained high-rate sacrifice in the months before maternity leave reduces your SMP for the first 6 weeks (where SMP is 90% of earnings).
If you are planning maternity leave, ask your employer how SMP is calculated and whether they top up. Many large employers pay enhanced maternity that uses pre-sacrifice salary for the calculation.
Life insurance pegged to salary
Some “death-in-service” employer benefits are calculated as a multiple of salary. Sacrificing salary may reduce the cover. Check the small print before increasing sacrifice meaningfully.
How to set it up
The mechanics:
- Ask HR for the salary sacrifice form (most large UK employers have one).
- Decide on a percentage or fixed amount to sacrifice.
- The form goes to payroll, which adjusts your contract terms.
- Your gross salary on payslips drops; your pension contribution line increases.
- Take-home reduces by less than the contribution because of the tax savings.
You can usually adjust the sacrifice once or twice a year, often at year-end or following pay review. Some employers allow more frequent changes.
The annual allowance limit
Salary sacrifice contributions count toward the £60,000 annual allowance for 2026/27. They also count toward the tapered annual allowance for high earners (those with adjusted income over £260,000 see their allowance taper down to £10,000).
For most people, the £60k cap is not binding—but high earners running close to it should check.
What I’d actually do
If you are employed in the UK:
- Check whether your employer offers salary sacrifice. If yes, use it.
- Find out if there is any employer NI pass-through. If not, ask.
- Sacrifice at least the percentage that gets you the full employer match.
- If you are a higher-rate taxpayer, especially in the £100k–£125k band, sacrifice aggressively.
- Don’t increase sacrifice in the six months before applying for a mortgage.
- Don’t sacrifice so much you fall below NMW or below the threshold for maternity benefits if relevant.
For UK basic-rate-paying employees, salary sacrifice is the easiest single optimisation in personal finance. For higher and additional-rate taxpayers, it is hard to beat—and easy to miss.
For the broader retirement context, see our UK pensions and retirement guide, and for how the tax relief mechanics interact with non-sacrifice contributions, see tax relief on pension contributions.
Frequently asked questions
- How much can salary sacrifice save me?
A basic-rate taxpayer typically saves 8% in National Insurance plus 20% in income tax—meaning each £100 contributed costs about £72 in lost take-home pay. If your employer also passes back their 15% employer NI saving, the net cost can drop to £60 or below.
- Does salary sacrifice reduce my mortgage borrowing capacity?
Yes, sometimes. Lenders use your reduced gross salary for affordability calculations, not your pre-sacrifice salary. Some lenders specifically uplift for documented salary sacrifice; many don't. If you are applying for a mortgage soon, check before sacrificing more.
- Can my employer refuse salary sacrifice?
Yes. Salary sacrifice is voluntary on both sides. If your employer doesn't offer it, you can ask, but they're not obliged. Most large employers offer it because it saves them National Insurance too.
