The short answer
You get one Personal Allowance for a tax year, even with two jobs. HMRC usually allocates it to the job that pays most and uses a different code for the other employment; the tax due depends on total income, not on the label “second job”. See HMRC's current guidance for more than one job.
Four checks when you take another job
Tell the new employer
If you keep an existing job, complete the starter checklist accurately rather than treating the new role as your only employment.
Read both payslips
Check the PAYE code shown for every employer and whether only one source is using the standard 1257L code.
Check HMRC's view
Use the Personal Tax Account or HMRC app to check employers, estimated income and the Personal Allowance allocation.
Keep income types separate
Employment through payroll, self-employed side work and company income do not all have the same reporting route.
One Personal Allowance across your income
HMRC's current guidance says you get one Personal Allowance for each tax year, even if you have income from more than one job, pension or another source. For 2026/27 the standard allowance is £12,570, although it is not the same for everyone. The question is how it is allocated, not whether a second employer can create another allowance.
When the main job pays more than the allowance, HMRC says the other employment's income will be taxed too, even if it is small. If the main job uses less than the allowance, unused allowance may be allocated to another job depending on the circumstances.
Why second-job tax codes differ
Each employer uses its PAYE code to work out deductions. HMRC says that with more than one job or pension, the sources will usually have different codes: one may use 1257L, while another may use BR, D0 or D1. Those codes are not interchangeable and do not by themselves show an error.
BR means all income from that source is taxed at the basic rate; D0 and D1 apply higher and additional rates respectively. Scotland and Wales have code and rate differences. Use the official tax-code guide and your full HMRC record instead of changing payroll instructions based on one payslip.
Starting the new employment
If you already work elsewhere, you will not receive a P45 from that continuing employer. HMRC says you should complete the starter checklist for the new employer and make clear that you have another job. This helps the employer apply the right code from the first payment.
After your first pay, check the PAYE section of your Personal Tax Account or the HMRC app. HMRC says it can show the current employers, estimated income, tax codes and which employment uses the allowance. Correct missing or wrong employment information through the official service.
A self-employed side hustle is different
Extra work is not always a second PAYE job. If you are employed and also carry out casual self-employed work, HMRC treats the self-employed income separately from PAYE tax taken from wages. The official guidance says you may need to use Self Assessment if self-employed income is more than £1,000; below that figure you may not need to tell HMRC or declare it, but the facts matter.
Keep records of the extra income and its costs from the start. Use our Self Assessment eligibility guide for the wider filing question and our sole-trader expenses guide if the extra work is a trade.
National Insurance is calculated separately
Your tax code controls PAYE Income Tax, not National Insurance. National Insurance is calculated separately on earnings from each job. That distinction is one reason a “tax on a second job” calculation should not be guessed from Income Tax alone.
Do not rely on a generic “second-job tax rate”
The result depends on total income, code allocation, the tax year, country of residence, benefits and whether the extra work is employment or self-employment. A payroll deduction can be reviewed; it is not proof of the final annual position.
What to have ready for a review
Keep each payslip, P45 or starter-checklist details, the current tax code for each job, and your best estimate of full-year income. For side work, keep income and cost records separately from employment documents.
Related guidance
Second-job tax FAQs
Do you pay more tax on a second job?
A second job does not create a separate extra rate of tax. Income Tax depends on your total taxable income for the tax year and how HMRC allocates your Personal Allowance and PAYE codes across employments. A second payroll may still deduct tax from its first payment.
Can I have the Personal Allowance on two jobs?
You have one Personal Allowance for the tax year, even if you have more than one job or pension. HMRC usually allocates it to the job that pays the most, but may split unused allowance between jobs in some circumstances.
What tax code is used for a second job?
HMRC says a second employment will usually have a different code. BR taxes all income from that source at the basic rate, D0 at the higher rate and D1 at the additional rate. The right code depends on total income and individual circumstances.
Do I need Self Assessment if my second job is self-employed?
Employment income and self-employed income have different reporting routes. HMRC says you may need Self Assessment where self-employed income is more than £1,000; use its official additional-income checker because the full circumstances matter.
General information only, not personal tax advice. Check the current HMRC position and your own PAYE and income records before taking action.