Second Job Tax Guide UK: BR Code, Tax Rates & What to Watch For

When working multiple jobs in the UK, understanding how your income is taxed becomes essential. Whether you’re freelancing in the evenings, picking up weekend shifts, or balancing part-time employment with a full-time role, the tax on a second job in the UK can significantly affect your take-home pay. In this comprehensive guide, we detail everything you need to know about managing taxation across multiple jobs from the BR tax code to current rates, allowances, and crucial pitfalls to avoid.

🧾 What Does “Tax on a Second Job” Mean?

In the UK, each job is taxed separately, but your tax-free allowance (the Personal Allowance) only applies to one job typically your main one. The second job, unless you explicitly request otherwise, is often taxed under the BR tax code, meaning it’s taxed at the basic rate of 20% from the first pound earned.

📌 The BR Tax Code: Why It’s Important

The BR (Basic Rate) tax code stands for Basic Rate, which applies 20% tax to all income under that code, without any tax-free allowance. If your second job uses this code:

• You won’t get a Personal Allowance for that job.

• All earnings from that second job will be taxed at 20%, regardless of your total annual income.

Example:

⚠️ Important: If your total income pushes you into a higher tax bracket, you may owe additional tax.

💼 Setting Up a Second Job the Right Way

When starting a second job, your new employer will ask for a P45 or Starter Checklist. If you don’t transfer your tax code or clarify your main employment, your second employer may default to the BR code.

Steps to Avoid Overpaying Tax:

1. Inform HMRC which job is your primary employment.

2. Request a tax code update if your BR code is incorrectly applied.

3. Use HMRC’s online PAYE service to check your code.

4. At tax year-end, submit a Self Assessment if needed.

📊 Tax Bands for 2025/26

Earnings from your second job are added on top of your main income, potentially pushing you into a higher tax band.

🧠 National Insurance on Second Jobs

National Insurance (NI) may apply to both jobs if you earn over the lower earnings limit in each. As of the 2025/26 tax year:

• £1,048/month (or £12,576/year): Earnings above this are liable for NI contributions.

• If both jobs exceed the threshold, you’ll pay Class 1 NI on both.

• HMRC may adjust overpayments automatically via PAYE reconciliation at year-end.

💡 Avoiding Common Mistakes

Mistake 1: Assuming You Get Two Personal Allowances

Only one Personal Allowance applies per person per tax year. Assign it to the job with the higher income.

Mistake 2: Ignoring Tax Band Impact

Your second job income may bump your total income into a higher tax bracket, incurring 40% or 45% tax on part of your earnings.

Mistake 3: Not Checking Tax Codes

Incorrect tax codes can lead to overpayment or underpayment, creating unexpected tax bills.

Mistake 4: Failing to Claim Tax Refunds

If you’ve overpaid due to a BR code misassignment, use form P50 or Self Assessment to claim a refund.

📋 When You Need to File a Self Assessment

Even if you’re employed, HMRC may require you to complete a Self Assessment if:

• You earn over £100,000 total.

• You have untaxed income (e.g., side business, freelance work).

• You wish to claim tax reliefs or refunds.

This helps reconcile all income streams, including from your second job.

📈 Maximising Take-Home Pay From a Second Job

Here are some strategies to retain more of your income:

• Expense Deductions: Claim allowable expenses if you’re self-employed in your second job.

• Salary Sacrifice: Where applicable, opt into pension schemes or benefits.

• Gift Aid or Tax-Free Childcare: Reduce taxable income via legitimate reliefs.

• Check Your Tax Code Every Year: Especially after pay rises or job changes.

🛠 Useful Tools & Resources

• Check your Income Tax

• HMRC Tax Code Notice

• Self Assessment Guide

• Second Job NI Calculator

✅ Key Takeaways

• The BR tax code on a second job applies 20% tax from the first pound earned.

• You can only use your Personal Allowance once, typically on your main job.

• Both jobs may be subject to National Insurance.

• Failing to manage your tax codes can result in higher tax bills or delays in refunds.

• Check your total income to understand if you’re entering higher tax bands.

📝 Final Thoughts

Understanding how tax on second job UK earnings works is essential for accurate budgeting and avoiding unexpected tax bills. With the right setup and proactive tax code management, you can maximise your earnings and minimise overpayments.

Always keep your employment records up to date with HMRC and regularly check your PAYE account to ensure everything aligns correctly.