Salary Sacrifice Calculator

What salary sacrifice does

Salary sacrifice is an arrangement where you agree to a lower contractual salary in exchange for a non-cash benefit — most commonly an employer pension contribution of the same value. Because your reduced salary is what's taxed, you pay less Income Tax and National Insurance than you would if you were paid the full salary and then contributed to a pension yourself.

Why it beats a personal pension contribution

A personal pension contribution only gets tax relief, not National Insurance relief — the National Insurance has already been deducted from your pay before the contribution is made. Salary sacrifice avoids employee National Insurance entirely on the sacrificed amount, because that amount never counts as your salary in the first place. Many employers also pass on some or all of the employer National Insurance saving as an extra pension contribution.

The net cost of the sacrifice

Because you're saving Income Tax and NI on every pound sacrificed, the actual reduction in your take-home pay is smaller than the amount going into your pension — this calculator shows both figures side by side, so you can see the gap between the pension benefit and the real cost to your monthly pay.

Things to check before sacrificing

Salary sacrifice reduces your contractual salary, which can affect salary-linked benefits like mortgage affordability assessments, life insurance multiples, statutory maternity/paternity pay, and some employer benefits calculated as a percentage of salary. It also can't take your salary below the National Minimum Wage. Check your specific scheme's rules before committing to a large sacrifice.

This calculator's scope

It models a single sacrifice against a single salary for one tax year, using standard PAYE thresholds. It doesn't check minimum wage compliance, doesn't model other benefits taken via salary sacrifice (cycle-to-work, electric cars), and doesn't include the employer NI saving your employer might pass back to you as extra pension contribution.

A worked example

A basic-rate taxpayer on a £35,000 salary sacrifices £3,000 into their pension. Without the sacrifice, that £3,000 of salary would have been taxed at 20% Income Tax and 8% employee NI, a combined 28% — so £2,160 would have reached their take-home pay and £840 would have gone to tax and NI. With salary sacrifice, the whole £3,000 goes into the pension, and the reduction in take-home pay is only the £840 they'd otherwise have paid in tax and NI — meaning a £3,000 pension contribution costs them roughly £840 in real terms rather than £3,000.

Common mistakes to avoid

The most common mistake is comparing salary sacrifice to 'not contributing at all' rather than to a personal pension contribution — the fairer comparison, since a personal contribution also gets tax relief, just not the National Insurance saving. Another is sacrificing an amount without checking it won't breach the pension annual allowance, which can trigger an unexpected tax charge on the excess. A third is ignoring the effect on salary-linked benefits like mortgage applications, where lenders often use your post-sacrifice contractual salary, not your pre-sacrifice one.

Other things sacrificed alongside pensions

Pension contributions are the most common salary sacrifice, but the same principle — a lower contractual salary in exchange for a benefit — underpins other schemes too, including cycle-to-work and some electric car leases. Each has its own eligibility rules and tax treatment, and this calculator only models the pension case, where the entire sacrificed amount converts pound-for-pound into a pension contribution.