In the UK, there’s no separate second job tax. You only get one tax-free Personal Allowance (£12,570 for the 2025/26 tax year). Because of this, the money you earn from your second job is usually taxed from the very first pound you make. This means your second job income is often taxed at the basic rate of 20%.
So, it’s not as simple as “two jobs = more tax.”
In this guide, we’ll cover everything you need to know about the second job tax, including:
- How much do you get taxed on a second job,
- Do you have to pay more tax on second job,
- How personal allowance impact your second job tax, and
- Much More..
Let’s get into it!
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How Much Do You Get Taxed On A Second Job?
You will likely be taxed on your entire income from your second job. Usually, at the Basic Rate of 20% right from the very first pound you earn. And at the Higher Rate of 40% if your combined earnings push you into a higher tax bracket.
The tax rate itself isn’t technically higher than your main job; the key difference is the loss of your tax-free Personal Allowance.
How Personal Allowance Impact Your Second Job Tax?
To understand your second job tax, you must first understand the Personal Allowance. This is the amount of income you can earn each tax year without paying any Income Tax.
For the 2025/2026 tax year, the standard Personal Allowance remains at £12,570.
The crucial point here is that you only get one Personal Allowance, no matter how many jobs you have.
The HMRC system is designed to allocate your entire Personal Allowance to your main job. Because this is usually the one that pays you the most. Since your main job uses up your full tax free allowance, your second job tax will typically be on all the money you earn there. Usually right from the first paycheck!
Why Your Second Job Taxed Differently?
Your second job tax starts from the very first pound when your personal allowance is already used up by your main job. Your second employer will likely use a “BR” (Basic Rate) tax code, which automatically taxes all earnings from that job at 20%.
How Income Tax Codes Work When You Have Two Jobs?
Your tax code is what tells your employer how much tax to deduct from your pay. When you start a second job, your second job tax code will almost certainly be different from your main job.
Your Main Job Tax Code
For the 2025/2026 tax year, if you have one job and are entitled to the full Personal Allowance, your code is most likely 1257L.
Check Out: Tax Code 1257L: A Complete Guide 2025
Your Second Job Tax Codes
The most common second job tax codes are:
- BR (Basic Rate): Yes, this is the most common second job tax code. It means all your income from this job will be taxed at the 20% basic rate. This is used when your total combined earnings from both jobs fall within the Basic Rate band.
- D0 (Higher Rate): Generally, this means all your income from this job is taxed at the 40% higher rate. This is applied if your main job’s salary is already high enough that your extra income from the second job pushes your total earnings into the Higher Rate tax bracket.
- D1 (Additional Rate): This means all your income from this job is taxed at the 45% additional rate. This is for high earners whose combined income from both jobs pushes them into the Additional Rate band.
- 0T: If your new employer doesn’t receive a P45 from you or if HMRC hasn’t yet notified them of the correct code, they might apply a 0T tax code. This code means no Personal Allowance is applied. And all your income is taxed at the prevailing tax rates (20%, 40%, or 45%) depending on your income level. If you see this, you should contact HMRC to resolve it quickly. Because you might be paying too much tax or too little.
Here are some examples based on different income levels:
Example 1: Total income is over the Personal Allowance
Let’s say your main job pays £25,000, and your second job pays £5,000. Your full Personal Allowance of £12,570 is used on your main job.
| Main Job | Second Job | |
| Annual Income | £25,000 | £5,000 |
| Personal Allowance Used | £12,570 | £0 |
| Taxable Income | £12,430 | £5,000 |
| Tax Rate | 20% | 20% |
| Tax Paid | £2,486 | £1,000 |
Note: Your second job is taxed on all its earnings, but your total tax paid for the year will be correct. Because your overall tax liability is calculated based on your total income.
Example 2: Total income is below the Personal Allowance
Imagine your main job pays £8,000 and your second job pays £4,000. Your total income is £12,000, which is less than the £12,570 Personal Allowance.
Your main job uses £8,000 of your Personal Allowance. So no tax is deducted from that job.
Your second job using a BR tax code will tax all £4,000 of your earnings at 20%, even though you are not supposed to pay any tax.
In this situation, you have overpaid tax. You can claim a refund from HMRC at the end of the tax year for the tax you have wrongly paid on your second job.
What Happens If You Move Into A Higher Tax Bracket?
Combining the income from both jobs could push you into a higher tax bracket. For the 2025/26 tax year, if your total income from all jobs exceeds £50,270, any income above that threshold will be taxed at 40%. And your second job’s tax code may be adjusted to “D0”.
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Do You Pay National Insurance On a Second Job?
Yes, you generally have to pay National Insurance (NI) contributions on earnings from a second job. Unlike the Income Tax Personal Allowance, which you only get once per person, National Insurance is generally calculated completely separately for each employment.
You start paying NICs in any job once your weekly pay goes over the threshold. For the 2025/2026 tax year, that point is £242 a week. You start paying employee Class 1 NICs once your earnings in that specific job go above the Primary Threshold (£242 a week or £1,048 a month). This difference means you benefit from the NICs-free threshold in both jobs, up to a point.
Example: How NICs Work with Two Jobs
| Element | Main Job (Weekly Pay) | Second Job (Weekly Pay) |
| Weekly Earnings | £350 | £150 |
| Primary Threshold (PT) | £242 (NI-free) | £242 (NI-free) |
| Taxable NICs Amount | £350 – £242 = £108 | £150 – £242 = £0 |
| NICs Deduction | 8% on £108 | 0% |
In this example:
- You pay NICs on £108 of your main job income.
- You pay zero NICs on your second job because its earnings are below the weekly threshold.
If you had only one job paying £500 a week, you would pay NICs on £258 (£500 – £242), which is significantly more.
Can You Avoid Paying More Tax Up Front?
Yes, you can. You might think you’re overpaying because your total income is below your personal allowance. Or if you prefer to have the tax deducted more evenly throughout the year, you can contact HMRC.
You can ask them to split your personal allowance between your jobs. Remember, this is only best if your income from both sources is stable. If you’ve overpaid, HMRC will usually issue a refund at the end of the tax year.
Check Out: How to Change Tax Code Online?
If Your Second Income Is Self-Employed
Some people don’t take a second job but earn money on the side through freelance work or a small business. In that case, HMRC sees you as self-employed, and the rules change again.
You need to let HMRC know you’re trading, and you’ll have to fill in a Self Assessment tax return every year. This is where you report your profit and pay whatever tax and NICs you owe.
There is a small bit of good news. Because in this way, you get a £1,000 trading allowance. So, if your total self-employed income is under that amount, you don’t have to pay tax on it. But if it goes over £1,000, you must register and declare it.
NICs for self-employed people also follow a different setup. Class 2 NICs are now optional and mainly matter if you want to protect your State Pension record. Class 4 NICs are based on profit. For 2025/2026, you pay 6 percent on profits between £12,570 and £50,270, and 2 percent on anything above that.
A Few Tips to Avoid Tax Problems
The biggest risk with a second job tax is having the wrong tax code, which can lead to underpaying tax and a shock bill from HMRC.
- Tell HMRC: As soon as you start your second job, notify HMRC. You can do this by using their online Personal Tax Account or calling them. This ensures they can update your tax codes promptly.
- Check Your Payslips: Always check the tax code on the payslip for both your main job and your second job. Make sure the codes (like 1257L and BR) reflect how you want your allowance split.
- Keep P60 and P45: Hold onto your P60 (from your main job at the end of the tax year) and any P45 (when you leave a job). These are essential for tax purposes.
- Complete a Self Assessment: If you are a high earner or have complex tax affairs, you need to submit a self assessment form. Yes, HMRC may simply ask you to complete a Self Assessment tax return each year to sort out any under/overpayments.
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The Bottom Line
Having a second job doesn’t necessarily mean you pay a higher percentage-wise than someone with one job. But because your personal allowance is likely used up by your first job, the second job tax often feels more. Simply, because it’s taxed from the first pound.
If you keep an eye on your tax codes and double-check things with HMRC, you can make sure you’re not overpaying. And, you might even get some money back at the end of the year.
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Disclaimer: The information about Tax on a Second Job, provided in this article including text and graphics. It does not intend to disregard any of the professional advice.