Second Job Tax: What You Actually Pay

Two jobs paying £22,000 and £9,000 leave you around £720 a year better off than a single job paying £31,000, on an identical income tax bill. The gap is National Insurance, which is worked out separately for each employment rather than on your total. The BR code on your second job looks punishing, and in most cases it collects almost exactly the right amount.

Last updated: 25 August 2026

What a second job actually costs

Your Personal Allowance is £12,570, and you get one of them. HMRC gives it to whichever job it has down as your main one, which leaves nothing to set against the second. So the second job gets a BR code, and 20% comes off every pound.

That reads like a penalty on the payslip. Add the two bills together, though, and you land on the same number as a single salary of the combined amount. The allowance was only ever going to be used once.

National Insurance is where the two situations come apart. Every employer works your NI out on the pay they give you, using the full £1,048 a month threshold, and none of them knows about the others. Two jobs get two NI-free thresholds.

On £31,000 a year	One job	£22,000 + £9,000
Income tax	£3,686	£3,686
National Insurance	£1,474	£754
Total deductions	£5,160	£4,440
Take-home	£25,840	£26,560

2026/27 rates for England, Wales and Northern Ireland. No pension or student loan. The £9,000 job pays £750 a month, under the £1,048 threshold, so 8% of £9,000 is never charged.

The £720 is the whole story. Income tax matches to the pound across both columns, and the second job escaped National Insurance because it was small enough on its own. Split the same £31,000 the other way round, £9,000 as the main job and £22,000 as the second, and the answer is identical. NI follows the pay, not the label.

The saving shrinks as the second job grows, because once it clears £12,570 it starts paying 8% like anything else. Above the Upper Earnings Limit of £50,270 the advantage reverses, which is covered further down.

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Take-home Pay Calculator

Enter both salaries added together to see the income tax due in total. Then run each job on its own for the National Insurance, which is charged per job.

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Where the coding goes wrong

Default coding works when your main job is comfortably the bigger one and neither job crosses a tax band on its own. Outside that, it misses in one of two directions, and only one of them fixes itself quietly.

When your main job pays under £12,570

This is the case that genuinely overtaxes you. Two part-time jobs at £8,000 each come to £16,000, on which you owe £686. What happens instead is that the main job collects nothing, because £8,000 sits inside the allowance, and the second job collects £1,600 under BR. You're £914 down for the year, and £4,570 of your allowance goes unused.

Ask HMRC to split the allowance across both jobs. Give them the expected pay for each and they reissue the codes, so the first job might go to 800L and the second to 457L. The tax then comes out right week by week. You'd get the money back anyway through a P800 refund after 5 April, so the split buys you the cash now rather than in the autumn.

When the second job crosses a band

This one runs the other way and ends in a demand. Your second job's code is set from the band your main job reached, and it applies that single rate to everything. If the second job's pay carries you over the next threshold, PAYE keeps charging the old rate and the shortfall builds all year.

HMRC usually spots it and reissues the code, often as a K code that claws the arrears back through your main job. That can arrive well into the following tax year, by which point the money is spent. See the guide to tax codes for what each code does and how to challenge one.

Scotland: the same two jobs, £911 worse

Scotland's higher rate of 42% starts at £43,663. In England, Wales and Northern Ireland the 40% rate waits until £50,270. That £6,607 gap is where second jobs come unstuck, because it's exactly the range a modest second job lands in.

Take a £40,000 main job and an £8,000 second job. The main job sits in Scotland's 21% intermediate band, so the second job is coded SD0 and taxed at 21% throughout. The combined £48,000 puts £4,338 into the 42% band. PAYE collects £7,231 across the two jobs against a true bill of £8,142, leaving £911 for HMRC to come back for.

The identical pair of jobs in England is coded BR at 20%, collects £7,086, and settles to nothing. Same salaries, same employer behaviour, and a four-figure difference in what turns up in the post. Check where you stand with the Scottish Income Tax Calculator.

Scottish second-job codes carry an S prefix and match the band your main job reached:

SBR. Everything at the basic rate of 20%.
SD0. Everything at the intermediate rate of 21%.
SD1, SD2 and SD3. The higher rate of 42%, the advanced rate of 45% and the top rate of 48%.

National Insurance isn't devolved, so the £720 saving in the first table applies in Scotland unchanged. The Scottish problem is income tax coding, and the fix is to tell HMRC what you expect both jobs to pay before the year runs away.

If the second income is self-employed

A side hustle works differently, because there's no employer to run PAYE on it. The first £1,000 of self-employed income in a tax year is covered by the trading allowance, and below that there's nothing to report. Above £1,000 you register for Self Assessment by 5 October following the end of the tax year, then file by the next 31 January. Both dates are in the tax deadlines guide.

The profit is taxed at your marginal rate, so a basic rate employee pays 20% on it and a Scottish intermediate rate employee pays 21%. Class 4 National Insurance is charged at 6% on self-employed profits over £12,570, which most side hustles never reach, and your employed earnings don't count towards that £12,570. Class 2 was abolished in April 2024. You can still pay it voluntarily to protect your State Pension record if the profits are small.

One change coming is widely reported wrongly. From 2027/28 the threshold for having to file a Self Assessment return on trading income rises from £1,000 to £3,000, with a simpler online service for the amounts in between. The trading allowance itself stays at £1,000. Income between £1,000 and £3,000 remains taxable: the paperwork gets lighter, the tax doesn't go away.

Three things that catch people out

Two jobs with the same employer get added together

The per-job National Insurance threshold only applies to unconnected employers. Two contracts with one employer, or with two employers carrying on business in association with each other, have to be aggregated and the NI worked out on the total. Two roles at the same NHS trust or the same council won't give you the £720. A supermarket job and a pub job will.

Student loan repayments are also worked out per job

Each employer applies the full repayment threshold to the pay it gives you. On Plan 2 that's £29,385, so two jobs paying £20,000 each produce no student loan deduction at all, on £40,000 of income. It's legitimate, and it's how PAYE works. If you file a Self Assessment return for any reason, HMRC totals your income and bills the difference, so treat the gap as deferred rather than saved.

Two well-paid jobs can overpay National Insurance

The 8% rate drops to 2% above the Upper Earnings Limit of £50,270, and each employer applies that limit separately. Two jobs paying above it charge you 8% on the first £37,700 twice, which is more than the annual maximum you can be asked for. Apply to defer with HMRC form CA72A before the tax year starts, or claim the overpayment back afterwards.

Most second jobs are paid by the hour rather than by salary, so the number worth knowing is what an hour is really worth after tax. On a BR code every hour of the second job is taxed at the same flat rate, which at least makes it easy to work out. Run it through the Salary to Hourly Rate Calculator before you agree the shifts.

Frequently asked questions

Do I pay more tax on a second job?

No. Income tax on two jobs adds up to exactly the same as income tax on one salary of the combined amount. The second job looks worse on the payslip because it has no tax-free allowance attached to it, so 20% comes off from the first pound. Your main job already used the whole £12,570.

Why is my second job on a BR tax code?

BR means basic rate, and it taxes every pound of that job at 20% with no allowance. It's the correct code for a second job when your main job already pays you more than £12,570. D0 taxes everything at 40% and is used when your main job has already filled the basic rate band. In Scotland the equivalents are SBR at 20%, SD0 at 21% and SD1 at 42%.

Do I pay National Insurance on both jobs?

Only on jobs that pay above the threshold on their own. National Insurance is worked out separately for each employment, using the full £1,048 a month threshold each time, so a second job paying less than that carries no NI at all. This is why two jobs usually beat one salary of the same total. The exception is two jobs with the same employer, or with employers connected to each other, where the earnings have to be added together first.

Is second job tax different in Scotland?

The rates are, and there's a trap the rest of the UK doesn't have. Scotland's 42% higher rate starts at £43,663 rather than £50,270, so a second job can push you over it while your code is still set from your main job's band. On a £40,000 main job and an £8,000 second job, PAYE collects about £911 too little and HMRC asks for it later.

How do I stop my second job being overtaxed?

Ask HMRC to split your Personal Allowance across both jobs. This matters when your main job pays less than £12,570, because the unused part of the allowance is otherwise wasted while the second job pays 20% on everything. Call HMRC or use your Personal Tax Account and give them the expected pay for each job. Anything you overpaid before the change is refunded after the tax year ends.

Do I pay tax on a self-employed side hustle as well as my job?

Yes, above £1,000. The trading allowance covers the first £1,000 of self-employed income in a tax year, and below that there's nothing to report. Above it you register for Self Assessment by 5 October after the tax year ends, and the profit is taxed at your marginal rate, because your job has already used your allowance and part of your basic rate band.