Key facts
- Personal Allowance of £12,570 normally sits on your main job
- Second jobs often use BR, D0, or D1 tax codes (SBR, SD0, or SD1 in Scotland)
- Income tax on the same total earnings is the same whether you have one job or two
- National Insurance is assessed separately on each job against the £12,570 primary threshold
Model your own figures with the second job tax calculator, see how tax codes work in our UK tax codes explained guide and how to read your payslip UK guide, and check single-job income tax with the income tax calculator.
Why your second job is taxed differently
HMRC applies your £12,570 Personal Allowance to your main job first. That means the first £12,570 of your main pay is tax free, but your second job has no allowance left, so income tax often starts on the first pound from that employer.
This is why a second job commonly uses a flat tax code such as BR, which taxes all pay from that job at the basic rate. It does not mean you pay a special penalty rate. Your total income tax for the year still depends on your combined earnings across both jobs.
Tax codes for a second job
BR taxes all income from that job at 20% with no Personal Allowance. D0 taxes all pay at the higher rate (40 percent). D1 taxes all pay at the additional rate (45 percent). Scotland uses SBR, SD0, and SD1 instead.
HMRC picks the code based on your expected total income. If your main job already uses your allowance, the second job gets one of these flat codes. See how codes appear on a payslip in our tax codes explained UK guide and payslip guide.
National Insurance on two jobs
Employee National Insurance works differently from income tax. Each job is assessed separately against the £12,570 primary threshold, so you can pay NI on both jobs if each pays above that level.
That also means two lower paid jobs can pay less NI overall than one combined job at the same total. At £40,000 split across two jobs of £20,000 each, total NI is about £1,189, compared with £2,194 on one £40,000 job.
Use the National Insurance calculator to see NI bands on a single salary in detail.
Do you pay more tax overall
No, not for the same total income. Income tax is calculated on your combined earnings, so the total bill is the same whether you earn it from one employer or two.
Worked example for 2026/27: one job at £40,000 pays £5,486 income tax. Split as £25,000 plus £15,000 across two jobs, total income tax is still £5,486 (£2,486 on the main job and £3,000 on the second).
National Insurance can differ because of the per job threshold, so your combined take home may be slightly higher or lower with two jobs even when income tax matches. The important point is that you are not charged a higher income tax rate just for having two jobs.
Second Job Tax Calculator
Enter your main and second job salaries to see income tax, NI, take home, and your likely tax code.
Self employment as a second income
If your second income is from self employment rather than PAYE, it is reported through self assessment. You pay income tax on your profits alongside your employed income, and Class 4 National Insurance may apply on profits above the small profits threshold.
See the full process in our self assessment guide UK. Side hustle income follows the same rules: keep records, register if required, and file your return by the deadline.
How to avoid overpaying
If both jobs pay less than the Personal Allowance, ask HMRC to split your allowance between them. That can reduce tax taken during the year rather than waiting for a reconciliation.
Check your tax codes on each payslip. Emergency codes or a wrong BR code when your combined income is low can mean too much tax is taken upfront. HMRC reconciles after the tax year and refunds overpayments, often through an adjusted tax code.
Check your codes early
When you start a second job, confirm the tax code on your first payslip. If it looks wrong, contact HMRC or use your personal tax account to request a split allowance or code correction.Related Calculators
Frequently Asked Questions
Usually from the first pound at basic rate through a BR tax code, because your Personal Allowance is used on your main job.
No, not for the same total income. The tax is just split because the allowance sits on one job.
It taxes all the income from that job at the basic rate of 20%, with no Personal Allowance applied.
Yes, if each pays above the £12,570 threshold. National Insurance is assessed separately for each job.
Yes, because each job has its own threshold, so income split across two jobs can fall under more of the NI free band.
Your employer reports it through PAYE, but you should check the tax code is right to avoid over or underpaying.
You report it through self assessment and may pay Class 4 National Insurance on the profits.
Ask HMRC to split your Personal Allowance if both jobs are low paid, and check your tax codes.
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James Hartley is a CIMA qualified financial analyst and Founder and Lead Financial Analyst at WhatsUK, with 8+ years in UK tax, payroll, and compliance. He builds every calculator on WhatsUK and authors all editorial content, ensuring every figure is verified against official HMRC sources before publication.
Sources & Official References
- GOV.UK Tax codes- Second job codes including BR, D0, and D1 for 2026/27
- GOV.UK Income Tax- How income tax applies across multiple employments
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Disclaimer: This calculator provides estimates based on standard HMRC rates for 2026/27. Results may vary based on individual circumstances. This is not financial advice. Always consult a qualified accountant or CIMA-qualified financial adviser for personal tax matters.