Take a £75,000 salary and sacrifice £10,000 of gross pay into a pension for 2026/27. That £10,000 sits inside the 40 percent higher-rate band, so giving it up saves £4,000 of income tax. It also sits above the £50,270 upper earnings limit, where employee National Insurance is only 2 percent, so the NI saving is £200. The combined saving is £4,200, which means the full £10,000 lands in the pension while take-home pay falls by only £5,800. The effective relief works out at 42 percent on every pound sacrificed. Someone caught in the £100,000 to £125,140 personal-allowance taper would see an even higher effective rate, because sacrificing salary there reclaims the withdrawn allowance as well.
Item
Amount
Sacrificed into pension
£10,000
Income tax saved (40%)
£4,000
National Insurance saved (2%)
£200
Net cost to take-home pay
£5,800
How it is calculated
Salary sacrifice reduces your contractual gross pay before any tax or National Insurance is worked out, so the saving equals the tax plus the employee NI that would have applied to the sacrificed slice. The tool computes your income tax twice, once on the full salary and once on the reduced salary, using the 2026/27 England, Wales, and Northern Ireland bands after the personal allowance and its taper above £100,000. It does the same for Class 1 National Insurance, charging 8 percent between the £12,570 primary threshold and the £50,270 upper earnings limit and 2 percent above. The difference between the two runs is your total saving. The effective relief percentage is that saving divided by the amount sacrificed, which is why a higher-rate earner beats the basic-rate figure of 28 percent. The full sacrificed amount reaches the pension because the employer pays it across gross, which is the key advantage over relief-at-source schemes that only recover income tax.
Frequently asked questions
Why is salary sacrifice better than RAS pension?
RAS only saves you Income Tax (claim higher rate via Self Assessment). Salary sacrifice saves Income Tax AND National Insurance, that's an extra 2-8% saving depending on band.
Does salary sacrifice affect my take-home pay significantly?
Your take-home pay falls by less than the sacrificed amount because you save the income tax and National Insurance that would have applied to that slice of salary. For a higher-rate taxpayer the net cost is typically 58p for every £1 sacrificed into a pension. The exact figure depends on which tax and NI bands the sacrificed amount falls across.
Is there a limit on how much I can sacrifice each year?
Your post-sacrifice salary cannot fall below the National Minimum Wage for your hours worked. Beyond that, pension contributions are capped by the annual allowance, which is £60,000 for the 2026/27 tax year, though this tapers down for higher earners with adjusted income above £260,000. Sacrificing into other benefits such as childcare vouchers or cycle-to-work schemes has separate limits set by the scheme rules.
Does salary sacrifice affect my State Pension entitlement?
Salary sacrifice reduces your contractual gross pay, so if the sacrificed amount brings your earnings below the Lower Earnings Limit (£6,396 for 2026/27) you would stop accruing a qualifying year for the State Pension. In practice most workers sacrifice amounts well above that threshold, so entitlement is unaffected. It is worth checking your National Insurance record on the HMRC Personal Tax Account if you are close to the minimum earnings level.