What an emergency tax code is
On an emergency code, your tax is worked out based on what you're paid in that week or month only. Normally PAYE is cumulative: it looks at your pay and tax so far in the tax year and gives you the right share of your allowance. An emergency code switches that off.
| Ending | When it's used | Example |
|---|---|---|
| W1 | You're paid weekly | 1257L W1 |
| M1 | You're paid monthly | 1257L M1, or S1257L M1 in Scotland |
| X | Your pay dates vary | 1257L X |
You may also see the word NONCUM (non-cumulative), which means the same thing.
Why you've been given one
- You've started a new job and your employer doesn't have your P45 or previous pay details.
- You've started getting company benefits, such as a company car, and HMRC hasn't updated your code yet.
- You've started receiving the State Pension alongside work or another pension.
- You've come back to work after time off, or had a first job after studying.
Useful tool
Paste your code from your payslip to see whether it's an emergency code and what it means.
Will I pay too much tax?
Often, yes — at least for a while. Because the code ignores what you earned earlier in the year, it can't give you any unused allowance from before you started. If you start a job part-way through the year after a gap, you'll typically pay more tax than you should until the code is corrected.
Sometimes the opposite happens — if you had a well-paid job earlier in the year, an emergency code can take too little tax, and you'll owe the difference later. Either way, it gets reconciled.
How to get it fixed
- Give your employer your P45 from your previous job. That lets payroll use the right figures straight away.
- If you don't have a P45, fill in your new employer's starter checklist accurately.
- Check and update your details in the HMRC app or your Personal Tax Account — for example, tell HMRC about the new job or end the old one.
- If you're still on an emergency code after 35 days, GOV.UK suggests updating your tax code online or contacting HMRC.
Lost your P45?
Your old employer can't issue a duplicate, but your details are still with HMRC — updating your employment in the HMRC app or Personal Tax Account does the same job.Getting overpaid tax back
Once HMRC sends your employer a corrected, cumulative code, any tax you've overpaid this year is usually refunded through your next pay packet. If the tax year ends before that happens, HMRC normally works it out and sends a P800 tax calculation, with a refund if you're owed one.
If you file a Self Assessment return, the overpayment is accounted for there instead — your P60 shows the total tax deducted. See claiming a tax refund through Self Assessment.
Understand the rest of your code
The rest of your code still matters — 1257L is the standard allowance, but other numbers and letters tell a different story. Our tax codes explained guide covers every letter, or try the tax code checker.