Two jobs calculator
Two employers, one tax position. Income tax is charged on the total, but National Insurance is charged separately by each job, which quietly works in your favour.
How this is calculated
Income tax is worked out on your combined income, because you only get one personal allowance no matter how many jobs you have.
National Insurance works differently. Each employer calculates it independently on what they pay you, so each job gets its own primary threshold. Two jobs of £18,500 pay noticeably less National Insurance than one job of £37,000.
Student loan repayments are also assessed per employer in practice, though this calculator applies the threshold once to the combined figure, which is the more conservative result.
HMRC normally allocates your full personal allowance to the main job and taxes the second under the BR code at 20% on everything. If your main job does not use the whole allowance, you can ask HMRC to split it and stop overpaying.
Rates used · 2026/27
| Personal allowance | £12,570, once across all jobs |
| NI primary threshold | £12,570, per employer |
| Employee NI | 8% to £50,270, then 2% |
| Second job tax code | usually BR, 20% on everything |
Last checked July 2026. Source: HMRC and gov.uk.
Worked example
A £28,000 main job and a £9,000 second job is £37,000 of gross pay. Income tax on the combined total is £4,886, using one personal allowance. National Insurance is only £1,234, because the second job sits below the threshold entirely. The same £37,000 in a single job would pay £1,954, so the split saves £720 a year. Take-home is £30,880.
Common questions
Why is my second job taxed at 20% from the first pound?
Because the BR code assumes your personal allowance is fully used by the main job. If it is not, you are overpaying and can ask HMRC to move part of the allowance across.
Do I really pay less National Insurance with two jobs?
Yes, if both are above the threshold, because each employer applies its own. It is a genuine quirk of the system rather than anything clever on your part.
Will I owe tax at the end of the year?
You can, if the codes are wrong or if the second job pushes you into the higher rate. HMRC usually corrects it through a code change, sometimes after the fact.
What if the second job is self-employed?
Then it is taxed as profit through Self Assessment with Class 4 National Insurance instead. Use the self-employed calculator for that side.