£18,000 Salary — 4% Pay Rise After Tax
A 4% pay rise from £18,000 to £18,720 adds £720 to your gross pay. After income tax and National Insurance, you keep £518/year (£43/month) extra.
Before vs after — annual figures 2025-26
| Before (£18,000) | After (£18,720) | Change | |
|---|---|---|---|
| Gross salary | £18,000 | £18,720 | +£720 |
| Income Tax | −£1,086 | −£1,230 | −£144 |
| National Insurance | −£434 | −£492 | −£58 |
| Take-home/year | £16,480 | £16,998 | +£518 |
| Take-home/month | £1,373 | £1,417 | +£43 |
| Effective tax rate | 8.44% | 9.2% |
England 2025-26 rates. Personal Allowance £12,570. See Scotland for Scottish income tax.
Why you keep less than 4% of your pay rise
A 4% pay rise of £720 sounds significant, but the effective marginal tax rate on this additional income is 0.28055555555555556% — meaning you only keep £518 of the £720 increase.
The marginal rate combines income tax (20% or 40% depending on your band) and employee NI (8% on earnings between £12,570 and £50,270, 2% above). A pay rise that pushes you into the higher rate band (above £50,270) will be taxed at 42% on the portion above that threshold.
Calculate your exact take-home pay
Other pay rises from £18,000
Understanding your pay rise after tax
When you receive a 4% pay rise from £18,000 to £18,720, the £720 increase in gross pay does not translate directly into more take-home pay. Income Tax and National Insurance are deducted from the additional earnings at your marginal rate — the rate that applies to the top slice of your income.
For most employees earning between £12,570 and £50,270, the marginal rate is 28%: 20% income tax plus 8% employee NI. Above £50,270, NI drops to 2% but income tax rises to 40%, giving a marginal rate of 42%. If your pay rise takes you over the £50,270 threshold, the portion above it is taxed at 42% rather than 28%.
If you want to maximise the benefit of your pay rise, consider salary sacrifice into a pension — contributions made this way reduce your taxable pay, effectively giving you the full gross value of part of your rise tax-free. You can also use a pension calculator to model the long-term impact.
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