Second job tax explained: why your second job is on a BR code, when 20% is correct, when it overtaxes you, and how to fix it with HMRC in 2026/27.
If you’ve picked up a second job and the first payslip landed with more tax taken off than you expected, you’re not imagining it. The whole wage got taxed, with none of it tax-free, and the code next to your name probably says BR.
That’s normal. It isn’t always right. Here’s how second job tax actually works, when the BR code is correct, when it’s quietly costing you, and how to fix it.
Your tax-free personal allowance of £12,570 sits on one job (your main one), so your second job is usually taxed from the very first pound, normally at 20% on a BR code.
There’s no separate, higher “second job tax rate” in the UK. You’re taxed on your total income across both jobs. It only feels punishing because the tax-free chunk you’re used to seeing isn’t applied to the second wage.
Every UK taxpayer gets one personal allowance for the year: £12,570 for 2026/27, frozen at that level until at least April 2028. You can only spend it once.
When you take a second job, HMRC leaves your allowance on your main job (tax code 1257L) and puts your second job on BR. BR means Basic Rate: your second employer taxes everything they pay you at 20%, with zero tax-free allowance.
Worked example. Say your main job pays £20,000 a year and your second job pays £5,000.
Now check that against the “proper” answer. On £25,000 of income the tax due is (£25,000 minus £12,570) at 20%, which is £2,486. Identical. When your main job already eats your whole allowance and you stay a basic-rate taxpayer, BR on the second job is exactly right.
BR isn’t the only second-job code. Which one you get depends on how much you earn overall.
D0 taxes the second job at 40%. HMRC uses it when your main job already pushes you into the higher-rate band, so every pound of the second job should be taxed at 40% too. D1 does the same thing at 45% for additional-rate earners.
0T is the odd one out. It gives no personal allowance but taxes across the normal bands (20%, then 40%, then 45%). You’ll often see 0T when a new employer has no starter information from you, no P45 and no completed starter checklist. It can overtax you, so if you’re on 0T and shouldn’t be, that’s worth sorting quickly.
Here’s where second job tax goes sideways. BR assumes your main job uses your full £12,570 allowance. If it doesn’t, you’re being overtaxed on the second job.
Picture a different setup. Your main job is part-time and pays £10,000 a year. Your second job pays £6,000.
Your real tax bill on £16,000 of total income should be (£16,000 minus £12,570) at 20%, which is £686. You’ve been charged £1,200. That’s £514 too much, purely because your spare allowance is stranded on the main job where there isn’t enough income to use it.
This is the single most common second job tax mistake, and it hits exactly the people who can least afford it: anyone whose main job is part-time, term-time, or low-hours.
Three steps, in order.
First, look up both codes. Open the HMRC app (free on iOS and Android) or sign in to your Personal Tax Account with your Government Gateway ID. It lists every job HMRC knows about and the code attached to each.
Second, do the maths in your head. If your main job pays comfortably over £12,570, BR on the second job is almost certainly correct and you can leave it. If your main job pays under £12,570, you’ve got unused allowance and BR is overtaxing you.
Third, if you’ve got spare allowance, ask HMRC to split it across both jobs. You can request this in the HMRC app, in your Personal Tax Account, or by calling HMRC on 0300 200 3300. They’ll move part of your allowance to the second job so each wage gets the right tax-free slice. Here’s what I’d check first: tell them roughly what each job pays annually, so they can weight the allowance sensibly rather than splitting it evenly down the middle.
The good news is that HMRC reconciles the year automatically. If you’ve overpaid before the code is fixed, you get it back, either through a later payslip or after the tax year ends via a P800 calculation.
Income tax looks at your combined income. National Insurance doesn’t. It’s worked out separately for each job.
For 2026/27, employee National Insurance is 8% on earnings between £242 and £967 a week, then 2% above that, charged per job. So if your second job pays under £242 a week, it has no National Insurance taken off at all, even though your main job is over the threshold.
That’s genuinely in your favour. Two jobs at £240 a week each pay no employee National Insurance between them, while one job at £480 a week would. It’s a rare case where the split actually saves you money, and HMRC doesn’t claw it back the way it does with income tax.
The mechanics of second job tax haven’t changed for 2026/27. The personal allowance is still £12,570, the basic rate is still 20%, and the higher-rate threshold is still £50,270. BR, D0, D1 and 0T all behave exactly as before.
What did shift, from April 2026, is that HMRC moved most tax code notices online. If your second job code changes, you’ll usually find out in your HMRC account rather than through a letter. So if a second job payslip suddenly looks different, check the app for a new notice before assuming payroll made a mistake.
One more thing worth flagging with the National Living Wage now at £12.71 an hour: more second jobs are tipping over the personal allowance sooner than they used to, which makes getting your codes right more valuable than it was a couple of years ago.
Second job tax plays out differently depending on the shape of your work. Here are the setups I see most often.
Full-time main job, weekend job on the side. Your main job uses your whole allowance, so BR at 20% on the weekend job is correct. If the weekend work pays under £242 a week you’ll also dodge National Insurance on it. This is the clean case, and there’s usually nothing to fix.
Two part-time jobs, neither big on its own. This is where allowance-splitting earns its keep. If job one pays £9,000 and job two pays £9,000, putting the full allowance on job one wastes £3,570 of it, because job one can’t use more than £9,000 of tax-free room. Ask HMRC to split the allowance, roughly £12,570 shared to match each wage, and you stop overpaying on the BR job.
A new main job plus an old one you’re winding down. When you switch which job is “main”, HMRC can lag behind, leaving your new higher-paying role on BR and your old one on 1257L. That’s the wrong way round and costs you, because BR ignores the allowance on the job that now needs it most. Flag the change in the HMRC app so the codes swap over.
In all three, the tool is the same: check both codes, and if the allowance is sitting where it can’t be fully used, ask HMRC to move it.
It’s worth seeing the after-tax reality before you commit the hours. Say your main job covers your allowance and you’re a basic-rate taxpayer. Every £100 your second job pays you is taxed at 20%, so you keep £80. If the second job is under £242 a week, no National Insurance comes off, so you keep the full £80 rather than £72.
So a £5,000-a-year second job in that position nets you around £4,000 after tax, or a bit more if it stays under the weekly National Insurance threshold. That’s the honest number to weigh against your time, not the £5,000 headline.
If you want to see what your real take-home should be across two jobs, before you ring HMRC, the NetPay app works out the tax and National Insurance on each wage separately and shows your combined take-home. Free to download.
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Not automatically. Second job tax feels higher because the whole of your second wage is usually taxed at 20% on a BR code, with no tax-free slice applied. But that is only correct if your main job already uses your full £12,570 personal allowance. Across both jobs you pay the same total tax you would owe on the combined amount, once HMRC has your codes set right.
BR stands for Basic Rate. It tells your second employer to tax every pound they pay you at 20%, with no personal allowance. HMRC uses it because your allowance is already sitting on your main job. If you are a basic-rate taxpayer overall, BR on the second job is usually right.
Check both tax codes in the HMRC app or your Personal Tax Account. If your main job does not use your full personal allowance, ask HMRC to split it across both jobs. You can do this in the app or by calling 0300 200 3300. Any overpayment from earlier in the year is refunded automatically once the code is corrected.
National Insurance is worked out separately for each job, not on your combined pay. So a second job that pays under £242 a week has no National Insurance deducted, even if your main job is well over the threshold. That is different from income tax, which HMRC does eventually add up across both jobs.
Want to see your actual take-home pay?
NetPay UK works out your real net pay after tax, NI, pension and salary sacrifice, for hourly, shift and variable-income workers. Free to download.
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A note on financial advice: NetPay UK calculates take-home pay based on official HMRC tax rules. This article reflects rules in force at the time of publication (17 July 2026). Tax rules change. For complex situations, consult a qualified UK accountant or visit gov.uk/income-tax.
