£18,000 vs £21,000 After Tax 2025-26
Side-by-side UK take-home pay comparison · Income Tax + National Insurance
You keep £2,160 more per year
Earning £21,000 instead of £18,000 gives you £180 more per month (£42/week). Of the £3,000 gross difference, you keep 72% after tax and NI.
£18,000 — Income Tax bands
| Band | Tax |
|---|---|
| Personal Allowance | — |
| Basic Rate (20%) | £1,086 |
| Total Income Tax | £1,086 |
£21,000 — Income Tax bands
| Band | Tax |
|---|---|
| Personal Allowance | — |
| Basic Rate (20%) | £1,686 |
| Total Income Tax | £1,686 |
Full breakdown — £18,000 vs £21,000
| £18,000 | £21,000 | Difference | |
|---|---|---|---|
| Gross salary | £18,000 | £21,000 | +£3,000 |
| Income Tax | £1,086 | £1,686 | +£600 |
| National Insurance | £434 | £674 | +£240 |
| Total deductions | £1,520 | £2,360 | +£840 |
| Net pay (annual) | £16,480 | £18,640 | +£2,160 |
| Net monthly | £1,373 | £1,553 | +£180 |
| Net weekly | £317 | £358 | +£42 |
| Net daily | £63 | £72 | +£9 |
| Effective tax rate | 8.44% | 11.24% | |
| Marginal tax rate | 28% | 28% |
£18,000 vs £21,000 after tax — what you actually keep
On a £18,000 salary, you take home £16,480 per year (£1,373/month). On £21,000, you take home £18,640 per year (£1,553/month). The £3,000 gross difference translates to £2,160 extra take-home — you keep 72% of the raise.
Income Tax on £18,000 is £1,086, rising to £1,686 on £21,000. National Insurance increases from £434 to £674. Together these deductions mean HMRC takes £840 of the £3,000 difference.
Why the effective rate changes
At £18,000 the effective tax rate is 8.44%, while at £21,000 it rises to 11.24%. This is because additional earnings are taxed at the marginal rate (28% on £21,000), which is higher than the blended average. The more you earn, the greater the proportion taken in tax and NI.
Frequently asked questions
How much more do I take home on £21,000 vs £18,000?
On £21,000 you take home £18,640/year (£1,553/month), compared to £16,480/year (£1,373/month) on £18,000. That is £2,160 more per year, or £180 more per month.
Why is the net difference (£2,160) less than the gross difference (£3,000)?
Of the £3,000 gross difference, you keep £2,160 (72%) after Income Tax and National Insurance. The rest goes to HMRC. Your marginal rate on £18,000 is 28% and on £21,000 it is 28%.
What is the effective tax rate on £18,000 vs £21,000?
The effective tax rate (Income Tax + NI as a percentage of gross) is 8.44% on £18,000 and 11.24% on £21,000. The higher salary has a higher effective rate because more income falls into higher tax bands.
How much tax and NI do I pay on £18,000 vs £21,000?
On £18,000: Income Tax £1,086 + NI £434 = £1,520 total deductions. On £21,000: Income Tax £1,686 + NI £674 = £2,360 total deductions.