Your situation
Tax code when you start a new job
Independent site, not HMRC. Only HMRC can change your code: use your HMRC online account or app.
What your new employer needs from you, the code it picks on day one, and when HMRC replaces it.
Should come back to you
£500.40
In your December pay (month 9), if the new code reaches payroll by then.
| Tax on 1257L M1 | £500.40 |
| Tax with 1257L over the same pays | £0.00 |
| Tax line on that payslip | −£500.40 |
Assumes no other pay earlier in the tax year. With a P45 from an earlier job, the refund depends on the tax already paid there.
A new employer sets your first tax code from one of two documents. If you hand over parts 2 and 3 of the P45 from your last job, payroll copies the code and the pay and tax to date printed on it, and your tax carries on as if nothing had changed (GOV.UK, P45). Without a P45 you fill in the starter checklist and tick one statement. Statement A, first job since 6 April with no Jobseeker's Allowance, Employment and Support Allowance or Incapacity Benefit, gives the current Personal Allowance on a cumulative basis: 1257L for 2026 to 2027 under HMRC's P9X notice. Statement B, another job or one of those benefits earlier in the year, gives the same allowance on a week 1 or month 1 basis. Statement C, another job or a pension still running, gives BR, with every pound taxed at 20%. HMRC then sends a proper code once it has the figures from both employers, which can take up to 35 days from your start date.
Starter checklist: which code?
Code the employer uses
1257L
| Tax in the first month | £250.20 |
| Basis | cumulative |
Rules read on HMRC’s texts by Radif Partners · Editorial policy · Method
What the new employer needs before your first pay
Your new employer must tell HMRC about you through its payroll submission on or before your first payday, and it needs a code to do so. The P45 from your last job is the best source: it shows your leaving date, the pay and tax since 6 April and the code you were on. Give the employer parts 2 and 3 and keep part 1A for your own records. If the P45 turns up after your first pay has already been reported, the employer instructions say to switch to the code on parts 2 and 3 at that point.
No P45, or a first job ever, means the starter checklist instead. It is a short form that you give to the employer, not to HMRC. Alongside the statement it asks about student and postgraduate loans, so the right deductions start with your first payslip.
Statements A, B and C and the code each one gives
The three statements decide how much allowance payroll applies straight away. The table follows HMRC's method for a pay of £2,300 a month, with 1257L as the current allowance for 2026 to 2027, and shows the tax on the first payslip depending on when the job starts.
| First pay in | Statement A, cumulative | Statement B, month 1 | Statement C, BR |
|---|---|---|---|
| April | £250.20 | £250.20 | £460.00 |
| July | £0.00 | £250.20 | £460.00 |
| October | £0.00 | £250.20 | £460.00 |
| January | £0.00 | £250.20 | £460.00 |
Statement A gains in value the later you start: the cumulative code gives you the allowance of every month since April, so a first job that begins in October may take no tax at first. Statement B ignores those months because you may already have used the allowance in an earlier job. Statement C never gives allowance at all. Payroll keeps whichever code it reported until HMRC sends a new one, so the choice matters for weeks, not just one payslip (tax codes for employers).
Starter checklist: which code?
Code the employer uses
1257L M1
| Tax in the first month | £250.20 |
| Basis | month 1, until HMRC sends a code |
Your first payslips
Look at the code printed on the payslip. A code ending in W1, M1 or X, or the word NONCUM, means the emergency basis, where each pay is treated on its own (emergency tax codes). It is usually temporary. When HMRC has the income details from both employers, it sends a code to you and the employer, and if too much was taken the excess is normally returned through your pay. If too little was taken, GOV.UK says you can stay on the emergency code until the year's tax is right.
Being paid by your old and new employer in the same month is one of the situations GOV.UK names as a reason for a tax calculation letter after the year ends, so keep your last payslip from the previous job.
When to act yourself
Give HMRC 35 days from your start date. After that, if the code still looks wrong, sign in to your HMRC online account, check that the old job shows an end date and the new one an estimated pay that is realistic, and correct what is missing (how to update your code). If your old employer never gave you a P45, ask them for one: see starting without a P45.