Salary Sacrifice Pension Calculator

Salary sacrifice reduces your gross contractual pay and your employer pays the sacrificed amount directly into your pension. Because the contribution comes from the employer, neither employee National Insurance (8% on earnings £12,570-£50,270) nor employer NI (13.8%) is payable on the sacrificed amount. Under relief at source, you contribute from net pay and only save income tax, not NI — so salary sacrifice is always more efficient when NI applies.

The calculation compares take-home pay under both methods. With relief at source on a £500 monthly contribution from a £40,000 salary, you pay from net pay and reclaim 20% basic rate relief, costing you £400/month. With salary sacrifice, your salary drops by £500 but you save £40 employee NI (8% of £500), so your net pay only drops by £360 — an extra £40/month reaching your pension or pocket.

Your employer also saves 15% NI on the sacrificed amount (£69 on £500). Many employers share part or all of this saving by adding it to your pension contribution. Salary sacrifice reduces your qualifying earnings for State Pension, statutory maternity pay, and mortgage affordability assessments, so the calculator flags when sacrifice would take earnings below the NI lower earnings limit (£6,708) or affect benefit entitlements.

Why salary sacrifice pension beats RAS for most workers. RAS (Relief at Source) pension: contribute £80 net from your post-tax salary, HMRC adds £20 basic-rate relief. Higher-rate taxpayers must claim extra 20% via Self Assessment. Salary sacrifice: contribute £100 gross, your take-home only drops by £68 (basic) or £58 (higher) — you save income tax AND National Insurance immediately. For higher-rate taxpayers, salary sacrifice saves an extra 42% (40% IT + 2% NI) vs RAS's 40%.

The employer NI 'passback' bonus. When you sacrifice £1,000 into pension, your employer saves 15% NI (£150) AND avoids 0.5% Apprenticeship Levy for large employers. Best-practice employers RETURN this saving as ADDITIONAL pension contribution — turning your £1,000 sacrifice into £1,150 in the pension. Ask HR if your scheme has 'NI passback'. If not, suggest it — costs employer nothing beyond admin.

Watch the floors: minimum wage and benefit thresholds. Salary sacrifice reduces gross pay used for: (1) National Minimum Wage check — sacrifice cannot take you below £12.71/hr × hours; (2) Statutory Maternity Pay calculation (uses sacrificed gross); (3) State Pension qualifying earnings; (4) Mortgage affordability assessment. For workers near NLW or trying to maximise SMP/maternity pay, careful sacrifice planning is essential. Pause sacrifice before maternity leave begins to maximise SMP earnings reference period.

The £100k cliff and 60% effective rate. Income £100k-£125,140 has effective 60% marginal rate (40% IT + 20% from Personal Allowance taper). Salary sacrificing this slice into pension is the most tax-efficient move in UK personal finance. £25,140 sacrifice from £125k income: cost to you ~£10,056, pension gain £25,140 = 60% effective relief PLUS the employer NI saving. Many high earners aim to keep adjusted income just below £100k via pension sacrifice.