Starting a second job is exciting — but then you see your first payslip and find you're being taxed at 20% from pound one, even on amounts you wouldn't pay tax on at all in your main job. This isn't an error. Here's why it happens and what you can do about it.
Why Second Jobs Get BR Code
You only get one Personal Allowance — the £12,570 that you can earn tax-free each year. HMRC assumes your primary job uses all of this allowance. Your second job, therefore, starts with zero remaining allowance, and the first pound is taxable at 20%. The BR code (Basic Rate, applied to all income at 20%) reflects this.
The Maths
If you earn £28,000 from your main job and £8,000 from a second job:
- Main job: £12,570 tax-free; 20% on remaining £15,430 = £3,086 tax
- Second job: 20% on all £8,000 = £1,600 tax
- Total tax: £4,686 — the same as if you earned £36,000 from one job
The BR code doesn't overcharge you overall — it just means the second job's deductions appear higher. Your end-of-year tax position is correct.
What If Part of Your Allowance Is Unused?
If your main job doesn't use your full personal allowance (for example, you only work 20 hours at £8/hour = £16,640 gross, leaving £3,930 of your allowance unused), you can ask HMRC to split the allowance between the two jobs. This would reduce tax on your second job.
Contact HMRC at 0300 200 3300 or via your Personal Tax Account to arrange a split code.
Frequently Asked Questions
Could my second job push me into the 40% tax bracket?
Yes. If your combined income from both jobs exceeds £50,270, the excess is taxed at 40%. The employer running your second job may not know about your first job's income and won't automatically change to a D0 (40%) code — but HMRC will calculate the correct total tax at year end and issue a P800 if you've underpaid.
Do I need to tell HMRC about my second job?
Your employer is required to report your income to HMRC via RTI (Real Time Information). HMRC will be aware of both jobs automatically. You don't need to actively notify HMRC, but if your combined income might push you into the 40% bracket, it's worth checking your cumulative position with our Two Jobs Tax Calculator.