What Happens to Your Tax When You Have Two Jobs in the UK?

More and more people across the UK are picking up a second job. Some do it to cover rising bills. Others want to save for something special. A few just want variety in their working life. Whatever the reason, the moment you start earning from two places at once, your tax situation changes – and it pays to understand exactly how.

The good news is that the UK tax system handles two jobs in a fairly logical way. The tricky part is that the logic is not always obvious until you know where to look. This guide walks you through everything clearly, from how your tax-free allowance gets split, to the tax codes that appear on your payslips, to the rules that can push you into a higher tax bracket without warning.

How Tax Works When You Have Two Jobs

In the UK, income tax is collected through a system called PAYE – which stands for Pay As You Earn. Under PAYE, your employer works out how much tax to take from your pay before they hand it over to you. They do this using a tax code that HMRC sends them.

When you only have one job, the system is straightforward. Your employer applies your full Personal Allowance – currently £12,570 – to your wages. You pay no tax on the first £12,570 you earn, and then tax starts above that.

When you add a second job, that changes. You only have one Personal Allowance, and it can only be used once. So HMRC assigns it to your main job – the one where you earn the most, or the one you started first. Your second job gets no tax-free allowance at all. Every pound you earn there gets taxed straight away.

Your Tax Code Tells the Story

The tax code on your payslip is one of the most important numbers to understand when you have two jobs. It tells your employer exactly how much of your pay is tax-free before they start deducting anything.

For your main job, you will usually see the code 1257L. This tells your employer to apply your full £12,570 Personal Allowance to your wages. As long as your earnings stay below that threshold, no tax gets taken.

For your second job, the code is different. The most common ones are:

• BR – Basic Rate. Every pound you earn at your second job gets taxed at 20%, with no tax-free element at all.
• D0 – Every pound is taxed at 40%, the higher rate. HMRC uses this when they expect your total combined income to put you in the higher tax band.
• D1 – This applies the additional rate of 45%. It is used when combined earnings are above £125,140.

These codes exist to make sure the right amount of tax is collected across both jobs together, not just one in isolation. If your second job code looks wrong, or if you see 1257L on both jobs, something has gone wrong – and you need to fix it quickly before a tax bill builds up.

What If Both Your Jobs Pay Less Than £12,570?

This is a situation that catches a lot of people off guard. If your main job pays less than your full Personal Allowance, and your second job also pays a small amount, putting all your allowance on the main job does not make full use of it. The unused portion just sits there while your second job gets taxed on everything.

There are two ways to handle this.

First, you can ask HMRC to split your Personal Allowance between both jobs. For example, if your main job pays £8,000 and your second pays £5,000, you could ask HMRC to allocate £8,000 of your allowance to job one and £4,570 to job two. This spreads your tax-free income fairly across both roles.

The downside is that this split needs reviewing regularly because if your earnings change, the arrangement can quickly become inaccurate.

Second, you can simply wait until the end of the tax year and claim a refund. If you have overpaid tax because your allowance was not being fully used, HMRC will send you money back. If they write to you asking for your P60 forms, make sure you have kept one from each employer, and always keep copies for yourself.

How National Insurance Works Across Two Jobs

Income tax is not the only deduction to think about. National Insurance Contributions (NICs) are also taken from your wages – and they work very differently from income tax when you have two jobs.

With income tax, HMRC looks at your combined income from all sources. But with National Insurance, each job is treated completely separately. Your two employers calculate your NICs independently from each other, without knowing what the other is paying you.

This means each job has its own NIC threshold. For 2025/26, employees pay 8% National Insurance on earnings between £12,570 and £50,270 per job.

If neither job individually pushes you past the upper threshold, you may end up paying less National Insurance overall compared to someone earning the same total from a single job because the lower earnings threshold resets independently for each job.

However, if your combined earnings across both jobs cross £50,270, you could end up paying National Insurance at the higher 2% rate on the top portion of earnings from one or both jobs. It is worth doing the sums for your own situation.

Could a Second Job Push You Into a Higher Tax Band?

Yes – and this is one of the most important things to understand before you start a second role.

Income tax bands in the UK apply to your total earnings from all sources combined. The higher rate of tax (40%) kicks in once your total income goes above £50,270. The additional rate of 45% applies above £125,140.

So even if your second job pays a modest amount, if your first job already takes you close to £50,270, the extra earnings from the second job can tip you into the 40% band.

When that happens, HMRC assigns a D0 code to your second job, and your earnings there get taxed at 40% from the very first pound.

For example:

• Main job salary: £46,000
• Second job salary: £8,000
• Total income: £54,000

The portion up to £50,270 falls into the basic-rate band, while the remaining £3,730 is taxed at 40%.

Many people only discover this when their first payslip from the new job arrives with far more tax taken than expected.

Next Read: How the £12,570 Personal Allowance Works And When You Lose It

When You Need to File a Self Assessment Tax Return

Most people with two employed jobs have their tax handled entirely through PAYE, with no need to file a tax return. But there are situations where you do need to complete a Self Assessment return yourself.

You need to register for Self Assessment if:

• Your total income from all sources goes over £100,000 in a year.
• You have self-employed income over £1,000 annually.
• Your PAYE tax codes are incorrect and leave tax owing.
• You want to formally claim a refund HMRC has not handled automatically.

The £1,000 figure is known as the trading allowance. Earn under that and you do not need to report it. Earn above it and you must register.

Common Mistakes People Make With Two Jobs

Not Telling HMRC About the Second Job

HMRC will eventually find out through payroll reports, but delays can cause incorrect tax codes and unexpected bills.

Seeing 1257L on Both Payslips

If both jobs use the full Personal Allowance, you are being under-taxed and may owe money later.

Assuming the Second Job Always Pays 20% Tax

If your combined earnings exceed £50,270, your second job could be taxed at 40% under a D0 code.

Forgetting the End-of-Year Reconciliation

HMRC checks total income and total tax paid. Overpayments generate refunds. Underpayments generate bills.

How to Check Your Tax Is Correct

The simplest way is through your HMRC Personal Tax Account. You can:

• View tax codes
• Check employer information
• Update income estimates
• Report mistakes

The HMRC app offers the same information on mobile devices.

If your code looks wrong, contact HMRC immediately so the issue can be corrected before the tax year ends.

A Quick Summary

• Your £12,570 Personal Allowance is normally assigned to one job only.
• Your second job is usually taxed under a BR code at 20%.
• If combined earnings exceed £50,270, a D0 code may apply and tax second-job income at 40%.
• National Insurance is calculated separately for each job.
• You can ask HMRC to split your Personal Allowance if neither job uses it fully.
• Self-employed income above £1,000 may require Self Assessment registration.

Frequently Asked Questions

Do I pay more tax overall just because I have two jobs?

No. Your total tax bill should be the same as if you earned the same combined amount from a single job. Two jobs only change how tax is collected.

What tax code will my second job have?

Usually BR (20%). If combined earnings exceed £50,270, it may become D0 (40%). Above £125,140, it may become D1 (45%).

Can I split my Personal Allowance between two jobs?

Yes. HMRC can divide your allowance between employers if neither job uses the full amount.

What if I have paid too much tax on my second job?

HMRC reviews your tax position at year-end and usually issues a refund automatically if you have overpaid.

Do I need to tell my second employer how much my first job pays?

No. However, you should complete your starter checklist accurately so HMRC can issue the correct tax code.

What if I freelance or do side-hustle work on top of two jobs?

If your self-employed income exceeds £1,000 in a tax year, you must register for Self Assessment and declare it.