What £100 in a pension costs a 40% taxpayer once all the relief is collected. But in one of the three common scheme types, only £20 of that relief arrives automatically — the other £20 has to be claimed, and frequently never is.
The principle is simple enough that it hides a genuinely important complication. Money going into a pension has not been taxed as income, so the government adds back the tax you would otherwise have paid. A £100 contribution costs a basic-rate taxpayer £80, a higher-rate taxpayer £60, and an additional-rate taxpayer £55.
The complication is that three different mechanisms deliver that relief, they behave differently, and almost nobody knows which one their employer uses. For higher and additional-rate taxpayers, the difference is money left unclaimed.
The Three Mechanisms
| Method | How relief arrives | Higher-rate relief |
|---|---|---|
| Relief at source | You pay from taxed income; the provider reclaims 20% and adds it to the pot | Extra 20% must be claimed yourself |
| Net pay arrangement | Contribution comes out before tax is calculated | Automatic — full relief given at source |
| Salary sacrifice | You give up salary; the employer pays it in instead | Automatic, plus National Insurance saved |
Only the first row leaves anything to do. If your scheme uses relief at source and you pay tax above the basic rate, the extra relief is yours but you must ask for it.
The Unclaimed Relief Problem
Under relief at source, the provider automatically adds basic-rate relief: contribute £80 and £100 lands in the pot. That is the whole of the relief a basic-rate taxpayer is entitled to, and the process ends there correctly.
A 40% taxpayer, though, is entitled to a further 20% — which is not added to the pension. It comes back as a reduction in your tax bill, claimed either through Self Assessment or by contacting HMRC to have your tax code adjusted. Nothing happens automatically, no letter arrives explaining it, and if you never claim, the relief is simply not given.
Find out which arrangement your workplace scheme uses, and if it is relief at source and you are a higher or additional-rate taxpayer, check whether you have been claiming. On £10,000 of annual contributions, the unclaimed portion is £2,000 a year for a 40% taxpayer. It is possible to claim for earlier years as well, within the usual time limits — so this is one of the few tax errors that can be partly undone retrospectively.
Salary Sacrifice: the One That Beats the Others
Under salary sacrifice you formally give up a portion of salary and your employer pays it into your pension instead. Because the money never becomes your pay, it escapes income tax and National Insurance — typically saving an extra 8–12% compared with an ordinary contribution.
Many employers also pass on part of their own NI saving as an additional contribution, which makes the gap wider still. Where sacrifice is offered, it is usually the best-value route into a pension available to an employee.
The trade-offs worth knowing before signing:
- Your stated gross salary falls. That can matter for mortgage applications, though most lenders will work with the pre-sacrifice figure if asked.
- Salary-linked benefits — death in service cover, some statutory payments — may be calculated on the reduced figure. Check the scheme rules.
- You cannot sacrifice below the National Minimum Wage, which limits it for lower-paid workers.
Our salary sacrifice calculator models the effect on take-home pay at your salary.
Where Relief Is Worth More Than the Headline Rate
The stated relief rates are the floor, not the ceiling. In two specific bands, a pension contribution is worth substantially more:
- Between £100,000 and £125,140, where the personal allowance is being withdrawn, the effective marginal rate reaches 62%. A contribution that brings adjusted net income back below £100,000 recovers the allowance as well as the tax — our adjusted net income guide works a £105,000 example where £5,000 into a pension saves £3,000 of income tax.
- Between £60,000 and £80,000 for parents, where the High Income Child Benefit Charge is being clawed back and a contribution reduces or eliminates it.
The Limits
Relief is capped by the annual allowance of £60,000 for 2026/27, or 100% of your earnings if lower. Contributions above the allowance do not receive relief — an annual allowance charge claws it back. High earners face a further restriction: above £260,000 of adjusted income the allowance tapers down to as little as £10,000, which our tapered annual allowance guide covers in detail.
For the great majority of employees these ceilings are irrelevant. Auto-enrolment minimums are 5% from you and 3% from your employer on qualifying earnings between £6,240 and £50,270 — nowhere near the limits, and for most people a good deal less than they should be saving. See our workplace pensions guide for what an adequate rate looks like.
Frequently Asked Questions
How much tax relief do I get on pension contributions?
Relief at your marginal rate. A £100 contribution costs £80 at the basic rate, £60 at the higher rate and £55 at the additional rate.
Do I have to claim higher-rate pension tax relief myself?
It depends on your scheme. Under relief at source, only the basic 20% is added automatically and the extra 20% must be claimed through Self Assessment or by having your tax code adjusted. Under net pay or salary sacrifice, full relief is given automatically.
What is the difference between relief at source and net pay?
Relief at source means you contribute from taxed pay and the provider reclaims basic-rate relief into the pot. Net pay means the contribution is deducted before tax is calculated, so relief at your full marginal rate is given immediately.
Is salary sacrifice better than a normal pension contribution?
Usually yes. Because the sacrificed pay never becomes your income, it avoids National Insurance as well as income tax, typically saving an extra 8–12%. Check the effect on salary-linked benefits before signing up.
Can I claim pension tax relief for previous years?
Yes, within the usual time limits for amending returns or making a claim. Higher-rate taxpayers in relief-at-source schemes who have never claimed are often owed several years of relief.
How much can I contribute with tax relief?
Up to the annual allowance of £60,000 for 2026/27, or 100% of your earnings if that is lower. Above £260,000 of adjusted income the allowance tapers down towards a £10,000 floor.
Related Guides
Keep reading with these related guides:
- Workplace Pensions Explained — auto-enrolment and how much to save
- Tapered Annual Allowance — the ceiling for high earners
- Adjusted Net Income Explained — where relief is worth 62%
- Pension vs ISA — choosing the wrapper
- Benefits in Kind and the P11D — how other workplace perks are taxed
- Salary Sacrifice Calculator — model the take-home effect
- All Tax Guides
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