Pension contributions are the single most powerful tool for reducing your UK tax bill. Every pound you contribute reduces your taxable income — and the government effectively tops up your pension pot with the tax you would have paid. This guide shows you exactly how much you save at each income level.
How the tax relief works
When you contribute to a pension, the money comes from your pre-tax income. The tax relief works differently depending on whether your pension uses "net pay" (salary sacrifice / employer contributions) or "relief at source" (personal pensions):
- Salary sacrifice / net pay: your gross salary is reduced before tax is calculated. You save both income tax and National Insurance automatically.
- Relief at source (personal pension): you contribute from after-tax income and the provider claims back 20% automatically. Higher/additional rate taxpayers claim the extra relief through Self-Assessment.
Effective rate of relief by band
- Basic rate (£12,571–£50,270): 20% income tax relief. Via salary sacrifice: additional 8% NI = 28% total.
- Higher rate (£50,271–£125,140): 40% income tax relief. Via salary sacrifice: additional 2% NI = 42% total.
- £100K–£125,140 trap zone: effective 60% income tax relief + 2% NI = 62% total. The most efficient zone to contribute.
- Additional rate (£125,140+): 45% income tax relief + 2% NI = 47% total via salary sacrifice.
Worked example: £60,000 salary, £5,000 contribution
Via salary sacrifice: your taxable salary drops to £55,000. The £5,000 was in the higher rate band, so you save:
- Income tax: £5,000 × 40% = £2,000
- Employee NI: £5,000 × 2% = £100
- Employer NI saving (often shared): £5,000 × 13.8% = £690
Your take-home pay drops by approximately £2,900 — but £5,000 (or more, if the employer shares their NI saving) goes into your pension. The effective cost to you is 58p for every £1 invested.
The "what if I maxed out?" scenario
The Annual Allowance is £60,000. For someone earning £80,000 who contributes the maximum via salary sacrifice, taxable salary drops to £20,000 — within the basic rate band. The tax saving is enormous: approximately £20,000+ in combined income tax and NI. Of course, your take-home pay is also significantly reduced — this only makes sense if you can afford it.
Model your own situation
The pension tax relief calculator shows your exact saving for any contribution amount. The salary sacrifice calculator compares before/after take-home. And for the full picture, the main calculator lets you toggle pension contributions and see the effect on your monthly pay.