Is a Second Job Worth It? The Honest Arithmetic
After the BR code, travel, childcare and the hours you lose, a second job often pays less than a pay rise you never asked for.
The BR tax code on a second job is not a penalty. It withholds 20% from the first pound on the assumption your Personal Allowance is already used against the main job, which for most people with two jobs is correct. If your main job pays under £12,570 you can and should ask HMRC to split the allowance.
The genuine advantage of two jobs is National Insurance: it is charged separately on each employment, so each gets its own nil-rate band up to the Primary Threshold. Two jobs at £12,000 each pay dramatically less National Insurance than one at £24,000.
What decides it is rarely the tax. It is the travel, the childcare, and — if you claim Universal Credit — a 55% taper applied to net earnings on top of everything else.
What a second job adds
| Main job | Extra tax and NI | Net from the second job | You keep | Net hourly at 10 hours a week |
|---|---|---|---|---|
| £16,000 | £2,240 | £5,760 | 72.0% | £11.08 |
| £24,000 | £2,240 | £5,760 | 72.0% | £11.08 |
| £32,000 | £2,240 | £5,760 | 72.0% | £11.08 |
| £42,000 | £2,240 | £5,760 | 72.0% | £11.08 |
| £55,000 | £3,360 | £4,640 | 58.0% | £8.92 |
The comparison to make
Take the net hourly figure in the last column, subtract the travel cost per hour worked and any childcare per hour, and compare it with an hour of overtime in your main job. Overtime involves no extra travel and no second employer, so it wins more often than people expect. The overtime calculator prices overtime the same way.
Questions people actually ask
Why is my second job taxed at 20% from the first pound?
Do I pay National Insurance twice?
The numbers this sits on
| Salary | Income tax | National Insurance | Take-home | A month | Effective rate |
|---|---|---|---|---|---|
| £25,000 | £2,486 | £994 | £21,520 | £1,793 | 13.9% |
| £35,000 | £4,486 | £1,794 | £28,720 | £2,393 | 17.9% |
| £45,000 | £6,486 | £2,594 | £35,920 | £2,993 | 20.2% |
| £60,000 | £11,432 | £3,210 | £45,358 | £3,780 | 24.4% |
| £85,000 | £21,432 | £3,710 | £59,858 | £4,988 | 29.6% |
| £110,000 | £33,432 | £4,210 | £72,358 | £6,030 | 34.2% |
Every figure in that table is computed from the published 2026/27 rates by the same engine that runs the calculators on this site, so a number in an article and a number in a calculator can never drift apart. National Insurance uses the statutory period thresholds real payroll uses, which is why these figures reconcile with a payslip rather than nearly reconciling with one.
| Salary | England, Wales, NI | Scotland | With a Plan 2 loan | Keep from the next £1,000 |
|---|---|---|---|---|
| £28,000 | 28.0% | 28.0% | 28.0% | £720.00 |
| £40,000 | 28.0% | 29.0% | 37.6% | £720.00 |
| £52,000 | 42.0% | 44.0% | 51.6% | £580.00 |
| £65,000 | 42.0% | 44.0% | 50.4% | £580.00 |
| £105,000 | 62.0% | 69.5% | 70.4% | £380.00 |
| £130,000 | 47.0% | 50.0% | 56.6% | £530.00 |
Work it out for yourself
- Take-home pay calculatorThe main calculator, all four UK nations.
- Pay rise calculatorWhat a raise really adds.
- Salary sacrificeWhat you are trading.
- Tax code checkerWhat each letter and prefix does.
Figures on this page are for the 2026/27 tax year (6 April 2026 to 5 April 2027) and were last checked on 29 August 2026. Every rate we use is listed on the sources page.