Pension Tax Relief Calculator

How pension tax relief works

What is pension tax relief?

Pension tax relief is the government's way of incentivising retirement saving: for every pound you contribute to a pension, the government effectively tops up your contribution based on the income tax you pay. At its simplest, a basic rate taxpayer contributing £800 to their pension has that topped up to £1,000 — the government contributes the £200 that would otherwise have gone in tax.

The principle is that pension contributions are made from pre-tax income. Because you have already paid income tax on take-home pay, the relief mechanism returns that tax to your pension pot. The higher your tax band, the more the government contributes — which makes pension saving particularly powerful for higher and additional rate taxpayers.

Relief at Source — how it works in practice

With Relief at Source (RAS), you contribute a net amount and your pension provider claims the basic rate (20%) from HMRC on your behalf, topping up your pot. So a £1,000 gross contribution requires you to pay only £800 — the provider claims £200 directly from HMRC. This happens automatically and applies to personal pensions, SIPPs, and many workplace schemes.

Higher rate (40%) and additional rate (45%) taxpayers receive only basic rate relief automatically through RAS. To claim the remaining relief, you must complete a Self Assessment tax return and request a rebate from HMRC. The effective cost for a higher rate taxpayer is £600 per £1,000 gross contribution (£800 paid in, £200 reclaimed via SA). For additional rate taxpayers the cost falls to £550. Importantly, non-taxpayers — such as children or non-working spouses — still receive the basic rate top-up via RAS, making it the only method that benefits them.

Net Pay Arrangements

Under a Net Pay Arrangement (NPA), your employer deducts your pension contribution from your gross salary before calculating income tax. This means you automatically receive relief at your marginal rate without any need for a Self Assessment return. However, there is a significant catch known as the "net pay anomaly": because relief is delivered by reducing taxable income, those who earn below the personal allowance — and therefore pay no income tax — receive no benefit at all. The government has been phasing in a top-up payment to affected workers, but it remains an important distinction when choosing a pension scheme.

Salary sacrifice — the most tax-efficient option

Salary sacrifice is an agreement between you and your employer to reduce your gross salary by the pension contribution amount. Because your headline salary is lower, you pay less income tax and less employee National Insurance. For a basic rate taxpayer, the combined saving is 28% (20% tax + 8% NI), dropping the effective cost of a £1,000 pension contribution to just £720. Higher rate taxpayers save 42%, and additional rate taxpayers save 47%.

A further advantage is that your employer also pays less employer National Insurance (13.8% on the sacrificed amount). Many employers pass some or all of this saving on to employees as an enhanced pension contribution. If your employer offers salary sacrifice, it is almost always the most tax-efficient way to contribute — though it requires a formal contractual change and may affect some salary-related benefits such as life cover or mortgage affordability assessments.

The annual allowance and carry forward

The annual allowance limits how much can be contributed to pensions each tax year with tax relief — currently £60,000 in 2026/27, or 100% of your earnings if lower. If you exceed this limit, you may face an annual allowance charge at your marginal rate. However, if you have unused annual allowance from the previous three tax years and were a member of a registered pension scheme in those years, you can carry that allowance forward and contribute more than £60,000 in a single year. Those with very high incomes (over £260,000) may have a tapered annual allowance reduced to as little as £10,000.

Pension contributions and the £100,000 trap

For higher earners with income between £100,000 and £125,140, the personal allowance of £12,570 is progressively withdrawn — £1 of allowance is lost for every £2 of income above £100,000. This creates an effective marginal tax rate of 60% on that income band. Pension contributions reduce your adjusted net income, which can restore the lost personal allowance. A higher earner on £110,000 who contributes £10,000 to their pension brings their adjusted net income back to £100,000, recovering their full personal allowance and effectively receiving 60% tax relief on that slice. This makes pension contributions one of the most powerful financial planning tools available to this group.