Is salary sacrifice worth it? The pros, the cons and the catches

Salary sacrifice saves income tax and National Insurance, and the employer may add its own NI saving on top. How large the saving is in a given case depends on the circumstances, and there are real trade-offs.

Where the saving is largest

The saving is largest when the employer passes on some or all of its NI saving; when the employee’s salary is below the upper earnings limit, so the employee NI saved is 8% rather than 2%; and when the sacrifice takes adjusted net income through a threshold — out of the £100k / 60% trap (the £100k tax trap calculator), back under the child benefit charge (the High Income Child Benefit Charge calculator), or below the £100,000 childcare cliff. In those bands the combined saving on the sacrificed slice can exceed the amount given up in take-home pay.

There is also nothing to claim. A higher- or additional-rate taxpayer paying a relief-at-source contribution gets only 20% added automatically and must recover the extra 20% or 25% through self assessment or a tax-code adjustment — a step that is routinely missed. Sacrificed salary is never taxed in the first place, so the full marginal-rate saving arrives in the payslip with no claim to make (see higher-rate pension tax relief: how it works and how to claim it).

The catches

It cannot reduce the employee’s pay below the National Minimum or Living Wage — which limits how much a lower earner can sacrifice. It lowers the salary used for some benefits: death-in-service cover (often a multiple of salary), statutory maternity and redundancy pay, and the income a mortgage lender will work from. It does not help with the tapered annual allowance — a post-2015 arrangement is added back to threshold income. Pension input above the available annual allowance, after any carry-forward, may trigger a separate tax charge; the allowance does not cap the contribution itself. And the money is locked away until at least age 55 (57 from 2028).

National Minimum Wage Act 1998 ; FA 2004 s.228ZA(5) (threshold-income add-back).

Cases where the trade-offs matter

Pay close to the National Minimum Wage, a mortgage application, a planned period of statutory parental leave and a salary-multiple death-in-service benefit are all affected by a lower salary. Each of these changes the arithmetic and should be weighed in the individual case. The salary sacrifice calculator shows the net cost and the amount paid into the pension side by side.

From 6 April 2029 legislation provides for a £2,000 annual cap on the National Insurance relief, to be brought in by regulations — salary sacrifice and the 2025 Budget.