Why your second job is taxed at 20%
Your £12,570 personal allowance is normally given to one job. The other job gets code BR, so everything you earn there is taxed at 20%. That's how the allowance is split, not extra tax.
When to ask HMRC to move your allowance
If your main job pays less than £12,570 a year, part of your allowance is wasted. You can ask HMRC to split it between your jobs, through your personal tax account or the HMRC app.
National Insurance
NI is worked out separately for each job in each pay period. If you earn below the threshold in a job, you pay no NI on it, even if your total across jobs is higher.
A worked example
Job 1 pays £9,000 a year and Job 2 pays £8,000. Your total is £17,000, so you should pay tax on £4,430, which is £886. But if all your allowance sits on Job 1, £3,570 of it is wasted, and Job 2 is taxed at 20% on its full £8,000: £1,600. You'd overpay by about £714 a year unless you ask HMRC to split the allowance.
How to split your allowance
Sign in to your HMRC personal tax account or the HMRC app, go to your tax codes, and tell HMRC how much you expect to earn in each job. HMRC will send each employer a new code. You can also call HMRC.
Getting overpaid tax back
If you've overpaid, it's usually refunded through your payslips once your code is corrected. For past tax years, HMRC normally sends a calculation after the year ends. You can check in your personal tax account.
Keep your own record
Shiftaan works out your hours and expected pay for every shift, even ones that cross midnight. Open the app.
Common questions
Why is my second job taxed so much?
Your tax-free allowance is usually used by your main job, so your second job is taxed at 20% with code BR.
Can I split my personal allowance between two jobs?
Yes. Ask HMRC through your personal tax account, the HMRC app, or by phone.