Wondering about second job tax and how it might affect your income? If you’re thinking about taking on a second job, it’s important to understand how taxes work—so you don’t underpay or overpay. Whether you’re doing it for extra income, to support your household, or simply because you enjoy it, knowing your tax responsibilities will help you avoid surprises.
Let’s explore the basics, how much tax you pay, and how to stay on top of it all.
The Basics: Can I Take a Second Job?
Before you start working a second job, consider these important points:
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Check your current employment contract. Some employers include clauses that restrict taking up additional employment, especially in similar industries or if it might affect your performance.
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Understand the working hours. Taking on more hours may affect your wellbeing or work–life balance.
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You must be paid at least the National Minimum Wage in both jobs.
There’s no law stopping you from having a second job, but make sure it doesn’t breach any of your primary job’s terms and conditions.
How Much Tax Do I Pay on a Second Job?
In the UK, HMRC considers your highest-paying job as your main job and applies your personal allowance (£12,570 for 2025/26) to it. Your second job is usually taxed at the basic rate (20%) from the first penny you earn, as it doesn’t get any personal allowance.
This is done using a tax code—typically:
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BR (Basic Rate – 20%)
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D0 (Higher Rate – 40%) if your total income is above £50,270
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D1 (Additional Rate – 45%) if your total income is above £125,140
Example:
If you earn £10,000 from your first job and £6,000 from your second job:
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Your first job will be tax-free (under personal allowance).
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Your second job income will be taxed at 20% using BR code.
If your total income from both jobs pushes you into a higher bracket, HMRC may change your second job tax code to D0 or D1.
How to Avoid Underpaying or Overpaying Tax
To stay accurate:
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Tell HMRC when you start a second job so they can assign the correct tax code.
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Provide a P45 from your first job or complete a starter checklist for the second job.
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Check your tax codes on your payslips. Your main job should have a code like 1257L, and your second job should have BR, D0, or D1 depending on your income level.
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Review your income regularly to ensure you’re not pushed into a higher tax bracket unknowingly.
Can I Split My Personal Allowance Between Jobs?
Yes—but only if your total income from both jobs is below the personal allowance (£12,570). You can ask HMRC to split your personal allowance across both jobs so you don’t overpay tax. You’ll need to contact HMRC to arrange this.
National Insurance (NI) on a Second Job
You also need to consider National Insurance contributions:
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You pay NI separately on each job.
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If you earn more than £242 a week in either job, you’ll pay Class 1 NI at 12% (for earnings between £242–£967).
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If you’re self-employed for one job, you’ll pay Class 2 and Class 4 NI through Self Assessment if profits exceed £1,000 per year.
What If My Second Job is Self-Employed?
If your second job is freelance or self-employed:
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You must register for Self Assessment with HMRC.
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Submit an annual tax return by 31 January.
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Pay tax and National Insurance (Class 2 and 4) based on your profits.
Even if your self-employed income is less than £1,000, it’s good to keep records and check whether you’re eligible for the trading allowance.
Conclusion
Now that you understand how second job tax works in the UK, you’re in a better position to plan your finances. The most important things to remember are:
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Inform HMRC as soon as you take on a second job.
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Watch your tax codes and total income to avoid overpaying or underpaying.
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Consider the impact of National Insurance and higher tax brackets.
Need Help with Tax Codes or a Second Job Setup? We advise on personal tax, prepare tax returns for sole traders and directors, and help you manage your PAYE jobs correctly. Our accountants in Croydon are happy to help.
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Disclaimer
The information in this article is for general guidance only. It does not replace professional advice tailored to your circumstances.
