Pillar guide · Salary sacrifice

Salary sacrifice for pensions — the complete UK guide.

How the NI saving works, why the £100k cliff makes it life-changing for high earners, the child benefit angle almost no one talks about, and the trade-offs on mortgages and maternity pay you need to know before you sign.

By Pension Bible editorial team·Last reviewed 8 April 2026·15 min read

What salary sacrifice actually is

Salary sacrifice is one of those phrases that sounds more complicated than it is. The mechanic is simple: you agree, in writing, to reduce your contractual gross salary by some amount each month, and your employer agrees to pay that same amount directly into your workplace pension as an employer contribution.

Because the money never hits your payslip as salary, it's never taxed as salary. You pay no income tax on it. You pay no employee National Insurance on it. And — this is the part most explainers skip over — your employer doesn't pay employer National Insurance on it either. All three of those tax savings are real cash that would otherwise have gone to HMRC, and they're now sitting inside your pension pot instead.

Compare that to the default way most personal pensions work, called relief at source. Under relief at source, you contribute out of post-tax salary and HMRC bungs the basic-rate tax back into your pension (and you claim any higher-rate relief via Self Assessment). That scheme recovers the income tax — but it does nothing about National Insurance. On a £1,000 contribution, a basic-rate taxpayer on relief at source gets £250 of tax relief added by HMRC. The same £1,000 routed via salary sacrifice saves £200 of income tax and £80 of employee NI, and if your employer passes on their own 13.8% NI saving, you get another £138 in your pot on top. That's the gap: same £1,000, very different outcomes.

You can run the exact numbers for your own salary using our salary sacrifice calculator or the pension tax relief calculator, which lets you flip between relief-at-source and salary sacrifice for the same inputs.

Why it beats relief at source for most people

The short answer is National Insurance. Relief at source only recovers your income tax — the NI you paid on the way in is gone forever. Salary sacrifice, by definition, means the money never counted as salary, so no NI was ever due.

For a basic-rate taxpayer earning between £12,570 and £50,270 the difference is a clean 8%. Every £1,000 you sacrifice saves you 20p of income tax and 8p of employee NI — a 28p saving on each pound, compared with the 20p saving you'd get from the same amount contributed via relief at source. Over a career of regular pension contributions, compounded inside a tax-wrapped pot for 25 or 30 years, that spread gets very large very quickly.

For a higher-rate taxpayer earning above £50,270 the income tax saving jumps to 40% but the NI saving drops to 2%. So sacrificing £1,000 at the higher rate saves you 42p per £1 in personal tax — versus the 40% relief-at-source equivalent that requires you to actively claim the extra 20p of higher-rate relief through Self Assessment. HMRC's own figures consistently suggest millions of higher-rate taxpayers never claim the relief they're owed under RAS. Salary sacrifice makes that problem disappear: the relief is automatic, immediate, and full.

For a worker earning £50,000, the difference between the two routes is not trivial — we break it down on the pension on £50k salary page. And for round-number intermediate cases like £30k, £40k and £75k, the same calculation framework applies with slightly different NI thresholds baked in.

The employer NI angle — the hidden kicker

Here's the part most guides underplay. When you salary-sacrifice, your employer stops paying 13.8% employer National Insurance on the sacrificed portion. That's real cash that used to leave their payroll budget and go to HMRC and now doesn't.

What happens to that saving is entirely up to the employer. Broadly, there are three models you'll find in the wild:

1. The employer keeps it. This is the default for a depressingly large number of UK schemes. The business banks a cost reduction every time a worker sacrifices. You still benefit from your own tax and NI saving, but the 13.8% vanishes into the employer's cost-of-sales line. It's still worth doing — just less worth doing.

2. The employer passes it on in full. Every penny of the 13.8% saving gets added to the pension contribution. So if you sacrifice £1,000, your employer pays £1,138 into your pension. This is the gold-standard model and it genuinely transforms the economics. Against a relief-at-source baseline at basic rate, the combined effective "top-up" on your £1,000 becomes around 41% rather than 25%.

3. Split or net-of-tax pass-through. Some schemes pass on the NI saving net of corporation tax (so about 75% of the 13.8%, or roughly 10.3%). Others split 50/50. Both are better than nothing and notably worse than full pass-through.

The distinction between a "basic" sacrifice scheme and a great one usually comes down to this single line of the policy document. If you're in a scheme that passes on the employer NI saving, you're in one of the most tax-efficient long-term saving arrangements the UK system offers. If you're in one that doesn't, the economics are still favourable — just not as dramatically so. It's worth asking HR what model your scheme uses before you decide what percentage to sacrifice; the answer often surprises people who have worked at the same employer for years and never thought to ask.

The £100k cliff — the most valuable use case in the UK tax system

If you earn between £100,000 and £125,140, stop and read this section twice. It is the single biggest reason salary sacrifice exists.

UK income tax has a quirk that doesn't get taught alongside the headline 20/40/45 rates: the personal allowance of £12,570 starts to be withdrawn once your adjusted net income crosses £100,000. You lose £1 of personal allowance for every £2 of income above £100k. The personal allowance is fully withdrawn by the time your adjusted net income hits £125,140.

In the £100,000 to £125,140 band, you are paying 40% income tax on each additional pound and losing 50p of personal allowance on each pound, which itself triggers another 20p of tax. That's a 60% effective marginal rate on every pound earned in that band. Add the 2% employee NI and the true take-home rate on a marginal pound is roughly 38p in every £1.

Now flip it. Salary sacrifice reduces your adjusted net income. For every pound you sacrifice in the £100k to £125,140 band, you save 40p of income tax, you reclaim 20p of personal allowance (which saves another 20p of tax in the tax that would otherwise have been charged on that reclaimed slice), and you save 2p of employee NI. The true cost to your take-home of every £1 going into the pension is around 38p. Put differently: a £10,000 sacrifice costs you about £3,800 in take-home pay and gets £10,000 (plus any employer NI pass-through) into your pension.

There is no other legal move in the UK tax system that turns 38p of net pay into £1 of saving. It is, pound for pound, the most valuable use of salary sacrifice anywhere in the income distribution.

For workers in this band, we have pre-filled context-specific versions of the calculator at £100,000, £110,000 and £125,000. The maths changes quite sharply across that £25k window and the pre-filled pages make the "what if I sacrifice back below £100k" scenario visible in pounds rather than percentages.

The child benefit angle (HICBC)

If you have kids and your household finances depend on child benefit, there's another marginal-rate story running in parallel at a lower income band. From 2024, the High Income Child Benefit Charge (HICBC) applies between £60,000 and £80,000 of the higher-earning parent's adjusted net income. Between those thresholds, child benefit is clawed back at 1% for every £200 of income — meaning it's fully withdrawn at £80,000.

The clawback can be substantial. A family with two children receiving child benefit gets around £2,200 a year in 2025/26. Across the £20,000 clawback band that's an effective extra tax of around 11% on each pound earned. Stack it on top of the 40% higher-rate income tax and 2% NI and you're looking at a blended marginal rate in the mid-50s.

Salary sacrifice reduces your adjusted net income. Bring your figure back under £60,000 and you recover the full child benefit entitlement. Even a partial reduction towards £60,000 claws back a proportion of it. For a lot of dual-earner households where one parent sits awkwardly in the £60k-£80k band, a modest increase in workplace sacrifice is the difference between paying HICBC and not paying it — and the money that would have gone to HMRC as the charge instead compounds inside a pension for 25+ years.

It's worth noting that child benefit itself isn't going anywhere: you still claim it, you just don't have it clawed back. This matters because child benefit claims protect the claiming parent's National Insurance credits for state pension purposes, so families should generally continue claiming regardless of HICBC status.

The trade-offs — what can go wrong

None of the above means salary sacrifice is a free lunch. The quiet cost is that, from the moment you sign the contractual variation, your "salary" as recorded by payroll is the lower figure. That has knock-on effects outside the pension world that you need to know about.

Mortgage applications. Mortgage lenders assess affordability against your post-sacrifice gross salary, because that's what appears on your payslip and P60. A worker on £55,000 sacrificing 10% into pension shows up as earning £49,500. With most lenders working on income multiples of 4.5x, that single change reduces theoretical maximum borrowing by around £24,750. Some lenders will add sacrificed amounts back on with documentation; many won't. If you're planning to buy or remortgage in the next 12-24 months, run the numbers on the affordability impact before you increase your sacrifice rate.

Statutory maternity, paternity, and adoption pay. These are calculated on average weekly earnings during a specific reference period — and sacrificed salary is not included. For someone who sacrifices heavily in the year before going on maternity leave, the SMP figure can come in noticeably lower than expected. Some employers top SMP up to full salary regardless; many do not. If you're planning to start a family, it's worth temporarily pausing or reducing sacrifice during the SMP reference period.

Death-in-service cover. Many UK employers provide death-in-service cover as a multiple (typically 2-4x) of base salary. That base salary is usually the post-sacrifice figure. On a £55,000 salary sacrificing 10%, that's around £5,500 less cover per multiple — so on a 4x policy, £22,000 of lost cover. Some schemes are written on "reference salary" instead, which protects against this; you need to read your own scheme's policy document to find out.

State pension entitlement. Salary sacrifice cannot reduce your gross salary below the National Insurance lower earnings limit (£6,396 in 2025/26) without starting to erode your qualifying year for state pension purposes. In practice this is only a risk for low earners or part-time workers with relatively small salaries and aggressive sacrifice percentages — most employers apply a floor to prevent this — but it's a real consideration for anyone working reduced hours.

Not all employers offer it. Salary sacrifice is a contractual arrangement, which means your employer has to agree to set it up and run it. Smaller employers sometimes don't bother because of the admin burden. Employers with multiple pension providers sometimes only offer sacrifice through one of them. If your workplace doesn't offer sacrifice, you're not out of luck — relief at source still works — you're just paying the NI that sacrifice would have avoided.

How to set it up at work

Salary sacrifice is, in legal terms, a variation of your employment contract. That means it's not something you can toggle on from a self-service HR portal in most organisations, although some larger employers with mature benefits platforms do automate it.

The standard sequence is:

1. Check with HR or the pensions/benefits team whether salary sacrifice is already available on your workplace scheme. The answer is usually yes at medium-to-large UK employers.
2. Ask for the scheme rules — specifically: does the employer pass on any of their employer NI saving, and if so how much? This is the question most people never ask, and it's the one that determines whether you're in a good scheme or a great one.
3. Complete the contractual variation form (sometimes called a "salary sacrifice election" or "flex choice"). This typically asks for the amount you want to sacrifice in £ or percentage terms, and the effective date.
4. Check the next payslip. Your gross salary should show the reduced figure, and there should be a line somewhere (often labelled "employer pension contribution") showing the sacrificed amount going into the scheme. If it doesn't appear correctly on the first payslip, escalate immediately — payroll errors in the first month of a new sacrifice arrangement are common.

Many schemes operate an annual enrolment window, meaning you can only change your sacrifice percentage once a year (usually during a flex benefits window in spring or autumn). Others let you change it whenever you like. Either way, it's worth timing larger sacrifice increases to align with bonus payments or pay rises, because the biggest marginal savings are usually on top slice of income.

Slide the numbers

This is the embedded salary sacrifice calculator from our tools hub. Change the salary, the sacrifice amount, and the employer NI pass-through toggle to see your specific take-home impact and pension contribution side by side.

Most people who run the calculator for the first time with realistic numbers are surprised by two things: how small the take-home impact is compared with the size of the pension contribution, and how much the result swings depending on whether the employer passes on their NI saving. Those two observations alone explain why salary sacrifice is the most-searched pension topic in the UK.

Salary sacrifice versus relief at source — when each wins

For the vast majority of working UK adults, salary sacrifice produces a better end result than relief at source. That's mostly because relief at source doesn't touch the NI, and NI is a real 8% (or 2%) drag that salary sacrifice sidesteps entirely.

There are, however, edge cases where the two are close or relief at source is actually preferable:

• Earners below the NI threshold (£12,570). If you're earning under the NI threshold, there's no employee NI to save. Sacrifice and RAS produce almost identical outcomes and the administrative simplicity of RAS often wins.
• Employers who don't pass on any NI saving and charge a platform or admin fee. A tiny minority of workplace schemes charge explicit management fees that differ between sacrifice and non-sacrifice members. These should be weighed against the tax saving.
• Workers deliberately trying to maximise mortgage borrowing. If a mortgage application is imminent, keeping headline salary high can be worth more than the sacrifice tax saving for the brief window before you exchange.
• Workers already at or above the annual allowance. Once you hit the £60,000 annual allowance (or a lower tapered figure), additional sacrifice triggers a tax charge that eats into — and can exceed — the saving.

Outside those exceptions, the numerical case for sacrifice is close to automatic. Our pension fees pillar guide has a parallel discussion of the other big variable in pension outcomes — what you pay inside the pot — and the two things compound together.

Tax-efficient sacrifice for high earners

High earners have two specific rules to watch that don't affect most savers.

The annual allowance. The standard cap on tax-efficient pension contributions (from all sources — employer, employee, sacrifice) is £60,000 per tax year for 2025/26. Contributions above this trigger an annual allowance charge that claws back the relief you otherwise would have received. The £60,000 figure is gross, so a £60,000 sacrifice fills it exactly with nothing left for employer contributions on top — in practice sacrificers with generous employer contributions need to leave headroom.

Carry forward. Unused annual allowance from the three previous tax years can be carried forward and used in the current year, provided you were a member of a UK-registered pension scheme during those years. For workers with irregular income or a sudden bonus year, carry forward is the mechanism that lets a single large sacrifice pull in up to three years of unused capacity plus the current year's £60k — a theoretical one-year contribution ceiling of £240,000 in unusual cases.

The taper for very high earners. Once adjusted income (broadly, taxable income plus employer pension contributions) crosses £260,000, the £60,000 annual allowance starts to taper away at a rate of £1 for every £2 over the threshold, down to a minimum of £10,000 for anyone with adjusted income over £360,000. Salary sacrifice reduces threshold income for this test (the other test used alongside adjusted income), so for workers near the taper boundary, sacrifice can sometimes be used to avoid triggering it — but the interaction is complex and is one of the handful of pension areas where paid advice from an FCA-regulated IFA usually pays for itself many times over.

FAQ

Is salary sacrifice always better than relief at source? For most working-age UK adults earning above the NI threshold and below the annual allowance, yes — the extra 8% (or 2%) NI saving on the sacrificed amount is pure additional relief that RAS doesn't deliver. Edge cases include workers below the NI threshold, imminent mortgage applications, and anyone already at the annual allowance ceiling.

How much can I sacrifice? There's no specific limit on sacrifice itself, but total pension contributions from all sources (employer, employee, sacrifice) cannot exceed the £60,000 annual allowance without triggering a tax charge. Some employers cap sacrifice at a percentage of salary. And you cannot sacrifice below the NI lower earnings limit (£6,396) without putting state pension qualifying years at risk.

Does salary sacrifice affect my state pension? Only if it drops your salary below £6,396 a year in 2025/26, at which point the year stops counting as a qualifying year for state pension. For anyone earning meaningfully more than that, the answer is no — your state pension entitlement is unaffected.

Does salary sacrifice affect my mortgage? Yes — lenders typically assess affordability against your post-sacrifice gross salary, which reduces the headline income multiple they'll lend against. Some lenders will add sacrificed pension contributions back on with documentation, but most won't. If a mortgage is imminent, check with your lender before increasing sacrifice.

Can I do salary sacrifice into a SIPP? No — not directly. Salary sacrifice is contractually between you and your employer, and the sacrificed amount has to go into the employer's nominated workplace scheme. You can, however, sacrifice into the workplace scheme and transfer accumulated balances into a SIPP periodically, which is a common approach for people who prefer the fund choice on a SIPP platform. See our pension fees guide for the cost considerations on both sides of that trade.

What happens to my salary sacrifice arrangement if I change jobs? The arrangement ends with your employment. At your new employer, you'd need to set up a fresh sacrifice election — they might use a different pension provider, a different contribution structure, and a different employer NI pass-through policy. This is a good moment to reassess whether the new scheme is worth sacrificing into at all.

Does HMRC need to know about my salary sacrifice? No — it's handled entirely through payroll. Your P60 will show the reduced salary figure, your tax and NI are calculated on that reduced figure automatically, and no separate claim or declaration is required. If you're in the £100k-£125,140 band or subject to HICBC, the reduced adjusted net income is reflected automatically on your tax return.

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Pension Bible is an editorial publication, not a financial adviser. The information in this guide is general guidance based on publicly available tax rules for the 2025/26 tax year. Tax treatment depends on individual circumstances and may change. Scottish taxpayers have different income tax bands. For personal recommendations about your specific pension arrangement, speak to an FCA-regulated financial adviser. You can find one through Unbiased or VouchedFor.