Tax on a second job explained

Does two jobs mean more tax?

This is the biggest myth about second jobs: that the extra job is taxed at some special, higher rate. It isn't. Income Tax is charged on your total income, so two jobs pay the same income tax as a single job on the same combined salary — assuming the same total taxable pay, pension treatment, benefits and reliefs. Earning £42,000 across two jobs costs the same income tax as earning £42,000 in one.

What changes isn't how much tax you owe — it's how it's collectedthrough the year. That's where the confusion (and the occasional surprise bill or refund) comes from.

How your Personal Allowance is split

Most people receive a Personal Allowance of £12,570 in 2026/27 (it tapers away once your income passes £100,000). With one job, your whole allowance sits against that job through tax code 1257L: the first £12,570 is tax-free, then the 20%, 40% and 45% bands apply.

HMRC normally allocates your Personal Allowance to one main job, but it can split the allowance between jobs where appropriate. So with two jobs, your main job usually keeps the full allowance (1257L) and the second job gets a BR code — unless you ask for the allowance to be split.

Why the second job is taxed at 20% (the BR code)

BR stands for “basic rate”. A BR code taxes every poundof that job at 20%, with no tax-free allowance — because your allowance is already used on the main job. It isn't a penalty; it's just collecting basic-rate tax on income that's already above your allowance.

If your combined income crosses into a higher band, 20% on the second job isn't enough. HMRC may use a D0 (40%) or D1 (45%) code on the second job, or adjust the code on your main job instead. A simple BR or D0 code can only approximate the result when the second salary spans more than one tax band — which is exactly why a year-end under- or over-payment can arise. In Scotland the equivalents are SBR, SD0and so on, using the Scottish rates.

Under-payments, over-payments and splitting your allowance

Because the codes only approximate the right answer, the amount collected through the year can be a little too much or too little:

• You may underpay if a BR second job is taxed at 20% but part of your combined income actually falls in the higher-rate band. HMRC usually corrects this by changing your code.
• You may overpay if your main job doesn't use your whole £12,570 allowance, yet the second job is still taxed at 20% on everything. Here you can ask HMRC to split your Personal Allowance across both jobs so less is taken up front.

National Insurance is worked out per job

National Insurance behaves differently from Income Tax. It's normally calculated separately for each employment and each pay period, and each job gets its own threshold — about £242 a week or £1,048 a month. You pay 8% between the primary threshold and the upper earnings limit, then 2% above it, on each job.

Because each job has its own threshold, a second job paying under it pays no NI at all— so two jobs can actually pay less National Insurance than the same money in a single job. On £30,000 + £12,000, the £12,000 job is under the threshold and pays no NI, saving roughly £960 compared with one £42,000 job.

Student loans across two jobs

Student loan repayments work like NI: each employer normally applies the repayment threshold to that job's pay only and ignores your earnings from the other job. So your combined earnings can be above the annual threshold even when nothing is deducted from either job.

There is not normally an automatic additional charge just because you have two PAYE jobs. However, if you complete Self Assessment, HMRC may work out an additional repayment using income from all relevant sources, after crediting what your employers already deducted through payroll. The two jobs calculator shows the per-job payroll deductions and any potential Self Assessment top-up when you pick your plan.

If you live in Scotland or Wales

Scotland sets its own Income Tax bands and rates, so the split works the same way but with S codes — S1257L on the main job and SBR (then SD0–SD3) on the second. Welsh taxpayers normally see a C prefix — such as C1257L or CBR — even where the rates currently match England and Northern Ireland. National Insurance and student loan rules are the same UK-wide. The Scottish income tax calculator uses the Scottish bands.

What to check

Two jobs rarely means paying more overall — but it's worth making sure your tax codes reflect your real income so you don't face a surprise. A common setup is 1257L on the main job and BR on the second, but your correct codes may differ — they can reflect a split allowance, company benefits, Marriage Allowance or a past underpayment. The key is that HMRC holds an accurate estimated income for both jobs, rather than assuming a particular code must be used. You can see and update your codes in the HMRC app or your Personal Tax Account.