How Is a Second Job Taxed? Two Jobs and Your Tax Code Explained
Taking on a second job often comes with a nasty surprise on the first payslip, and a common belief that second jobs are penalised by the taxman. They are not — but the way tax codes work makes it look that way.
The myth and the reality
There is no extra rate for having two jobs. HMRC simply adds your income together and taxes the total in the normal bands. What changes is where your tax-free personal allowance is applied. It is usually given entirely to your main job, so your second job has none — meaning every pound of it is taxed straight away. That is why the second job can feel heavily taxed even though your overall bill is exactly what it would be on the same total from one job.
What the tax codes mean
Your main job typically carries the standard code (1257L) that includes your full allowance. Your second job is often given a BR code, meaning all of it is taxed at the basic 20% rate, or D0 (40%) if you are a higher-rate taxpayer. These codes are HMRC's way of taxing the second income without double-counting your allowance.
The National Insurance quirk in your favour
National Insurance is different: it is calculated separately for each job, and each job gets its own threshold before any is due. That can work in your favour. Consider £30,000 from one job and £12,000 from another:
The same £42,000 earned in a single job would attract about £2,354 in National Insurance — so splitting it across two jobs saves roughly £960. Your Income Tax on the £42,000 total is the same either way.
If your code looks wrong
If both jobs pay below your personal allowance, you may be overtaxed on the second one — you can ask HMRC to split your allowance across them. If you overpay during the year because of how the codes are set, HMRC reconciles it and refunds the difference, usually after the tax year ends; contacting them can sort it out sooner.
The bottom line
A second job is taxed on your total income, not at a special rate — the BR code just front-loads the tax because your allowance sits with your main job. National Insurance, calculated per job, can even leave you slightly better off. Check your real combined take-home before assuming the worst.
Try the two jobs calculator →
Common questions
Sources
GOV.UK — Repaying your student loan, House of Commons Library — student loan interest & thresholds. See our full methodology and rates.
This article is general information for the 2026/27 tax year and not personalised financial advice. Check your own loan details in your student loan account and verify figures against GOV.UK before making decisions.