Pay guide · emergency tax
On an emergency tax code? Here's what it means.
Seeing W1, M1, X or NONCUM after your tax code, and a different amount of tax than you expected? It's common when you start a new job, and it's usually temporary.
UK guide · sources checked October 2026
The short answer
You're on an emergency tax code if your code ends in W1, M1 or X, or your payslip says NONCUM — for example 1257L M1. Your tax is worked out on that week's or month's pay only, as if you were paid the same every period, so you may pay the wrong amount. HMRC usually sends you and your employer an updated code within 35 days of starting a job, and any overpaid tax is then normally refunded through your pay.
What the letters mean
- The number and letter (for example 1257L) set your tax-free allowance. 1257L is the standard £12,570 Personal Allowance, but an emergency code can use a different number.
- W1 (week 1) is used when you're paid weekly; M1 (month 1) when you're paid monthly.
- X is used when your pay dates vary. Some payroll software shows NONCUM instead.
If your code doesn't end in W1, M1, X or NONCUM, you're not on an emergency code. Codes like BR (all pay taxed at 20%), 0T (no tax-free allowance) or D0 (all pay taxed at 40%) can also mean more tax, often for a second job. See what your tax code means on GOV.UK.
Why you might be on one
- You started a new job and your employer doesn't have your previous income and tax details.
- You started working for the first time.
- You started receiving a company benefit or State Pension.
How to sort it out
- Give your new employer the P45 from your last job. If you didn't get one, ask your previous employer for it.
- Check your tax code and income details in your HMRC personal tax account or the HMRC app, and update them if they're wrong.
- HMRC sends the updated code to you and your employer. This can take up to 35 days from when you start.
If you overpaid, the refund normally comes through your pay once the new code is used. If you've left the job or it isn't put right, you can claim a tax refund on GOV.UK. If you underpaid, you may stay on the emergency code until it's paid.
How to check your own payslip
Look for the tax code near your name or pay date, then compare the tax deducted with earlier payslips. A change alongside W1, M1, X or NONCUM is the usual sign. My Netto reads your payslip and points out the tax code and what it means for you, quoting your figures.
Sources
Official GOV.UK guidance, checked October 2026. Figures change each tax year. GOV.UK and HMRC are the authority; this guide is general information, not tax advice.
For workers
See what your own payslip says.
Upload a UK payslip to My Netto. It shows your tax code, what came off and whether anything looks unusual, with the figures taken from your payslip.
Check my payslipFor payroll and HR teams
Answer these questions before they reach you.
Netto delivers payslips on WhatsApp and answers employees' pay questions from their own payslip, with the source shown. Fewer “why was I taxed so much?” emails after every pay run.