UK Salary Sacrifice Pension Calculator

Salary Sacrifice Guide

How Salary Sacrifice Works?

Salary sacrifice reduces your contractual gross salary by the pension contribution amount before tax and NI are calculated. Because both tax and NI are charged on the lower salary, you save both. A basic rate taxpayer sacrificing £200/month: saves £40 income tax (20%) plus £20 NI (10%) = £60 saved. The £200 pension contribution costs only £140 in take-home pay. Higher rate: saves £80 tax + £20 NI = £100 saved — the £200 contribution costs only £100. This makes salary sacrifice far more efficient than making the same pension contribution from already-taxed income and claiming relief afterwards.

What's the key thing to understand about Employer NI Saving?

Employers also save 13.8% NI on salaries above the secondary threshold (£9,100/year in 2026/27). When an employee sacrifices £200/month, the employer saves approximately £27.60/month in employer NI. Many employers pass this saving to the employee's pension — making it even more tax-efficient. Always ask your HR or payroll department whether your employer operates an NI sharing arrangement. Even where they do not, salary sacrifice remains the most tax-efficient way to contribute to a pension for most employees, even before counting any employer NI saving passed back.

What should I know about Important Considerations?

Salary sacrifice reduces your contractual salary — this can affect: mortgage affordability calculations (lenders use gross salary, though many now understand salary sacrifice arrangements). State benefit entitlements (some benefits reference gross salary). Life cover and income protection (often calculated as a multiple of salary). Death-in-service benefits. Crucially, your adjusted gross salary must not fall below the National Living Wage (£12.71/hour in 2026/27) — sacrifice cannot take your salary below this floor, and most payroll systems will automatically cap the sacrifice amount to prevent it.

What should I know about Optimising Your Contribution?

The £100,000 personal allowance trap: if salary sacrifice brings your adjusted net income below £100,000, you recover Personal Allowance that is otherwise tapered away at an effective 60% rate. Sacrificing salary above £100,000 to below £100,000 recovers £1 of allowance per £2 sacrificed — creating an effective 60% tax relief rate on those pounds. Similarly, if you are just above the higher rate threshold (£50,270 in 2026/27), salary sacrifice that reduces salary below this threshold switches that portion of income from the 40% higher rate band back to the 20% basic rate, making the marginal tax saving on that slice of sacrifice particularly valuable.

What's the key thing to understand about How Salary Sacrifice Saves Tax and NI?

Salary sacrifice works by formally reducing your contractual salary in exchange for a non-cash benefit — most commonly additional pension contributions, but also sometimes cycle-to-work schemes, electric car leasing, or childcare vouchers (for those still eligible under older schemes). Because the sacrificed amount never counts as salary in the first place, it isn't subject to income tax or employee National Insurance, giving a bigger effective boost than simply contributing the same amount from net pay — a basic-rate taxpayer sacrificing into a pension effectively gets both the income tax relief a normal pension contribution would attract and an NI saving on top, since normal pension contributions (even with tax relief added) don't escape NI. Many employers also pass on some or all of their own NI saving on the sacrificed amount as an extra contribution into the employee's pension, which is pure additional benefit with no cost to the employee — it's worth specifically asking whether your employer does this, since not all do automatically. The sacrifice does lower your official salary figure, which can occasionally affect salary-linked things like mortgage affordability assessments, life insurance multiples tied to salary, or statutory maternity pay calculations, so it's worth checking those interactions before sacrificing a large proportion of salary.

What should I know about Salary Sacrifice and the Minimum Wage?

There's an important legal limit on how far salary sacrifice can go: your contractual salary after sacrifice cannot fall below the National Minimum Wage or National Living Wage for the hours you work, and employers are required to check this before agreeing to a salary sacrifice arrangement. This mainly affects lower earners, for whom sacrificing a large percentage of salary into a pension could otherwise, in theory, push effective hourly pay below the legal minimum — in practice, most employers cap the sacrifice automatically or won't offer it below certain salary levels to avoid this issue. It's also worth being aware that salary sacrifice reduces your salary for the purposes of calculating things like statutory redundancy pay, some means-tested benefits, and occasionally mortgage or loan affordability assessed by lenders who look strictly at contractual salary rather than total remuneration — none of these make salary sacrifice a bad choice for most people, but they're worth checking if you're close to a benefit threshold, planning a mortgage application in the near future, or anticipating redundancy, since the pension tax and NI savings need to be weighed against these secondary effects on a case-by-case basis rather than assumed to be purely beneficial in every circumstance.

Worked Example: £2,400/Year Pension Contribution via Salary Sacrifice

For a basic-rate taxpayer sacrificing £200/month (£2,400/year) of salary into a pension, using rates currently typical in the UK (basic-rate tax 20%, employee NI roughly 8% above the primary threshold, employer NI roughly 15% above the secondary threshold — these NI rates are reviewed most tax years, so treat them as illustrative):

The tax relief is available either way — the real extra benefit of salary sacrifice specifically is the employee NI saving (guaranteed) plus any employer NI saving the employer chooses to redirect into your pension on top (not guaranteed, varies by employer policy).

Why Salary Sacrifice Doesn't Help Everyone Equally

Salary sacrifice reduces your contractual gross salary, which can have knock-on effects beyond tax and NI: it can reduce mortgage affordability assessments (lenders often use post-sacrifice salary), lower life insurance or income protection payouts if these are salary-linked, reduce statutory maternity/paternity pay calculations, and affect means-tested benefit calculations like Universal Credit differently to a standard pension contribution. It can also push an income near the National Minimum Wage below the legal floor, which is why employers must cap how much low earners can sacrifice. For most mid-to-higher earners the net effect is positive, but anyone close to a salary threshold, applying for a mortgage soon, or near minimum wage should check the specific knock-on effects before increasing their sacrifice percentage.

Salary Sacrifice vs Simply Increasing Pension Contributions

Some people assume salary sacrifice and a standard increased pension contribution are the same thing with different paperwork — they aren't. A standard contribution is paid from your take-home pay after both tax and National Insurance have already been deducted, with tax relief added back afterward; salary sacrifice instead reduces your gross salary before either tax or NI is calculated, so NI is never charged on that portion at all. That's a real, permanent difference in take-home value, not just a timing difference in when relief arrives, which is why salary sacrifice is usually the better route for anyone whose employer offers it and who isn't near a salary-sensitive threshold.

The Point at Which Salary Sacrifice Can Reduce Entitlement to Other Benefits

Because salary sacrifice formally reduces your contractual gross salary rather than simply redirecting net pay, it can affect anything calculated from that headline salary figure — statutory maternity or paternity pay, some employer-provided life insurance or income protection multiples, mortgage affordability assessments that use payslip gross pay, and in some cases entitlement to tax credits or Universal Credit calculations, since these use different definitions of income that don't always treat sacrificed pension contributions the same way as take-home pay does. For most people on a reasonable salary with no immediate plans around maternity leave or a mortgage application, these effects are minor compared to the tax and NI saving, but anyone in those specific situations should check with their employer or a financial adviser how a planned sacrifice might interact with a near-term benefit or application before committing to it.