How UK Tax Actually Works
“I don’t want a pay rise — I’ll lose money to tax.” No, you won’t. Here’s why.
The Biggest Misconception in Finance
Many people believe that if they earn just above a tax threshold, ALL their income gets taxed at the higher rate. This is completely wrong and causes people to turn down pay rises, overtime, and promotions for no reason.
The UK uses marginal tax rates. Each band only applies to income within that band.
Key Concept
Think of tax bands like a stack of glasses at a champagne tower. You fill the first glass (personal allowance — tax-free), then overflow into the second glass (basic rate), then the third (higher rate). You only pay the higher rate on the income that “overflows” into that glass.
2024/25 Tax Bands
| Band | Income Range | Tax Rate |
|---|---|---|
| Personal Allowance | £0 – £12,570 | 0% |
| Basic Rate | £12,571 – £50,270 | 20% |
| Higher Rate | £50,271 – £125,140 | 40% |
| Additional Rate | Over £125,140 | 45% |
Worked Example: Earning £55,000
- First £12,570: taxed at 0% = £0
- Next £37,700 (£12,571 to £50,270): taxed at 20% = £7,540
- Final £4,730 (£50,271 to £55,000): taxed at 40% = £1,892
- Total tax: £9,432
- Effective tax rate: 17.1% (not 40%!)
Real-World Example
If you earn £50,270 and get a £1,000 raise to £51,270, you only pay 40% tax on the extra £1,000 — that’s £400 in tax, leaving you £600 richer. You NEVER lose money by earning more (except in one specific trap…)
The 60% Tax Trap (£100k–£125,140)
There IS one trap. If you earn between £100,000 and £125,140, your Personal Allowance is gradually withdrawn — you lose £1 of allowance for every £2 earned over £100k. The effect? A marginal rate of 60% in this band.
Warning
Earning £100,000 to £125,140 is the worst place to be for tax efficiency. If you’re in this range, pension contributions are incredibly powerful — they bring your adjusted income below £100k, restoring your Personal Allowance and effectively giving you 60% tax relief.
How to Legally Reduce Your Tax Bill
- Pension contributions — reduce your taxable income
- ISAs — investments grow tax-free
- Marriage Allowance — transfer £1,260 of unused Personal Allowance to your spouse (saves £252)
- Salary sacrifice — exchange salary for pension contributions (saves NI too)
- Gift Aid — higher/additional rate taxpayers can claim back on charitable donations
- Capital Gains Allowance — £3,000 tax-free gains per year