Starting a new job? That’s great, but do you know you might spot an unfamiliar tax code on your first payslip? Yes, you may be on an emergency tax code if your tax code ends in W1, M1, or X. This basically happens when HM Revenue and Customs (HMRC) does not yet have enough information about your income or previous employment.
However, know that being placed on an emergency code does not necessarily mean you have done anything wrong. Let’s understand what an emergency code is, why it happens, how to check your tax code, and whether you pay too much or too little income tax.
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What is an Emergency Tax Code?
An emergency tax code is a temporary PAYE tax code. This code is used when HMRC does not have enough information to calculate your normal tax code accurately. So, if you are starting a new job and your previous pay and tax details are not available, you may get an emergency code.
Additionally, emergency codes can be used in some circumstances when you start receiving State Pension or certain company benefits. It can take up to 35 days from the date you start your job to update your tax code after receiving the necessary information.
How do Emergency Tax Codes Work?
Currently, HMRC identifies emergency codes by the suffixes W1, M1, or X. You may also see NONCUM on your payslip, depending on your employer’s payroll software. You might see an emergency tax code that normally ends in W1, M1, or X. For instance, 1257L W1, 1257L M1, and 1257L X.
For the 2026/27 tax year, the standard emergency code is 1257L. The 1257L part reflects the standard £12,570 Personal Allowance. You may also see tax codes such as BR or 0T in Pay As You Earn (PAYE).
However, these are not emergency tax codes. BR means all income from that job or pension is taxed at the basic rate. Whereas 0T means no Personal Allowance is available for that source.
What do W1, M1 and X Mean?
An individual is on an emergency tax code if their tax code ends in.
- W1 is used when you are paid weekly.
- M1 is used when you are paid monthly.
- X is used when your pay dates vary.
Moreover, a NONCUM may appear on your payslip depending on your employer’s payroll software.
How Do I Know if I’m on an Emergency Tax Code?
You can check whether you are on an emergency code in several ways, such as:
Your Payslip
Check the tax code on your payslip. An emergency tax code usually ends in W1, M1, X, or NONCUM. For example, 1257L W1 or 1257L M1 specifies that the code is being operated on a non-cumulative basis.
The HMRC App
You can also use the HMRC app to view your tax code. Compare the code shown by HMRC with the code on your payslip to check whether they match.
Your HMRC Personal Tax Account
Sign in to your Personal Tax Account through the official government website. Check the tax code HMRC currently has for you and the employment or pension it relates to.
Your P45
If you have recently changed jobs, check the tax code on your P45. Then compare it with the code on your new payslip.
A different code does not automatically mean you are on an emergency tax code, because HMRC may have issued your employer with an updated code. If your new payslip has a code ending in W1, M1, X, or NONCUM, this indicates that the code is being operated on an emergency basis.
Why Might HMRC Assign an Employee to an Emergency Tax Code?
HMRC may assign an employee an emergency code when HMRC or the employer does not have enough information to calculate the correct PAYE tax code. This usually happens when an employee starts a new job, and their previous employment or tax details are not yet available.
Remember, being on an emergency tax code does not necessarily mean you will overpay tax. You could pay too much or too little tax while the temporary code is being used, depending on your circumstances. Emergency codes can be used when you:
Start a new job Without Providing a P45
Your new employer may put you on an emergency code if they don’t have details of your previous employment and tax record. Giving the right starter information helps your employer work out how to set up your PAYE record.
Start a new PAYE job After Being Self-Employed
Moving from self-employment to employment does not automatically result in an emergency tax code. However, you may be placed on one if HMRC or your new employer does not yet have enough information to establish the correct PAYE code.
Start Receiving Taxable Pension Income or the State Pension
Your State Pension and certain pension income can affect your tax position. HMRC may adjust your PAYE tax code so that the appropriate amount of tax is collected.
Have Taxable Company Benefits
Your tax code can be affected by benefits such as a company car or private medical insurance. HMRC could change your code when it gets information about your benefits. However, having a taxable benefit does not mean you will automatically be put on an emergency tax code.
Have More than one Employment
If you have more than one job, HMRC might give you different tax codes for your different sources of PAYE income. While having more than one job doesn’t automatically put you on an emergency tax code, changing jobs can sometimes result in a temporary code being issued.
If HMRC later receives or obtains the information it needs to work out your tax position, it may issue an updated tax code to your employer. Your employer then implements the new code through PAYE. If you have overpaid tax, then you may be refunded depending on your circumstances, either through the revised code or a subsequent HMRC calculation.
If you’re unsure why your tax code has changed, you can check your current tax code and employment details in your HMRC Personal Tax Account.
How to Stop an Emergency Tax Code?
To stop an emergency code, check your tax details through HMRC’s “Check your Income Tax” service. Review your tax code, estimated income and employment details, Personal Allowance, and update any incorrect information.
If you have recently started a job, do not forget to give your P45 to your new employer. If you do not have one, complete the starter checklist.
When HMRC has enough information, it can provide your employer with an up-to-date tax code to use through PAYE. The timing will vary depending on your situation.
Will I get a Refund From Emergency Tax?
Yes, you may be able to get a refund if you have paid too much tax because of an emergency tax code.
How do I Claim Back Emergency Tax?
If your tax code changes during the tax year, your employer will generally adjust your PAYE through the payroll system. If you are still due a refund after the tax year, HMRC may issue a P800 tax calculation to tell you how to claim it.
You may be able to claim the refund through your Personal Tax Account or the HMRC app, depending on your circumstances.
Furthermore, if your P800 says you can claim online, you are normally paid within 5 working days. You will be sent the money within 6 weeks if you have asked HMRC to send you a cheque.
When Might You Get an Emergency Tax Code on Pension Withdrawals?
When you first receive a taxable payment from a pension, you may be given an emergency tax code, particularly if your pension provider does not yet have the information they need to apply your correct tax code. This means more tax is deducted from the first payment than you end up paying.
Your pension provider might be working on a Month 1 (M1) or Week 1 (W1) basis. This means that your payment is taxed as if it was the first payment in that tax year and will not take your previous income into account.
What Is the Difference Between Cumulative and Non-Cumulative Tax Codes?
A cumulative tax code calculates your tax based on your total earnings and tax-free allowance from the start of the tax year to date. It allows your Personal Allowance and tax bands to be taken into account across the year.
In contrast, a non-cumulative tax code treats each pay period independently, ignoring everything you earned or paid before. With a non-cumulative tax code, your tax is calculated only on the current pay period, without taking previous pay or tax paid in the tax year into account. Codes ending in W1, M1, or X are operated on a non-cumulative basis.
Additionally, non-cumulative codes are commonly used as emergency tax codes. However, not every W1/M1/X code is necessarily caused by an emergency tax situation.
How Long Does an Emergency Tax Code Stay in Place?
An emergency code is temporary. It normally stays in place until HMRC has enough information to issue the appropriate tax code. No fixed period applies to everyone.
If you provide the necessary information, HMRC can update your tax code and send the new code to your pension provider or employer. If too much tax was deducted, the adjustment may result in a refund through payroll or from HMRC, depending on your circumstances.
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Summary
An emergency tax code is a temporary PAYE code. It is issued when HMRC does not have enough information to give the correct tax code. Codes ending with W1, M1 or X are for non-cumulative treatment, often used for emergency tax.
If you start a new job, give your P45 or fill in the starter checklist if you don’t have it. Make sure your details are correct by checking your HMRC Income Tax account. Also, if you have overpaid tax, your tax code may be adjusted and the overpayment corrected through payroll where appropriate.
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