You check your payslip and the tax deduction looks much higher than expected.
Then you spot something unfamiliar beside your tax code: W1, M1, X or NONCUM.
You may have been put on an emergency tax code.
It can be frustrating, particularly when it affects the amount arriving in your bank account, but an emergency tax code is usually temporary and can often be corrected once HMRC has the information it needs.
What is emergency tax?
Your tax code tells your employer or pension provider how much Income Tax to deduct from your pay.
Normally, PAYE takes account of your income and tax paid so far during the tax year.
An emergency tax code works differently. Your tax is calculated using only the pay for that particular week or month, rather than taking account of what has happened earlier in the year.
That can mean you pay more or less tax than you ultimately owe.
How do I know if I am on an emergency tax code?
For the 2026/27 tax year, the standard emergency codes are:
1257L W1
1257L M1
1257L X
Some payroll systems may show NONCUM instead.
W1 means Week 1, M1 means Month 1 and X is generally used where pay dates vary.
The important part is the ending. 1257L by itself is not an emergency tax code.
Why have I been put on emergency tax?
One of the most common reasons is starting a new job.
Your new employer needs information about your previous pay and tax to operate PAYE correctly. This will usually come from your P45.
If that information is not available when your first payroll is processed, your employer may need to use a temporary tax code.
You could also be placed on an emergency code after a change in your circumstances, including starting to receive certain company benefits or the State Pension.
I don’t have a P45. What happens?
Not having a P45 does not mean your employer cannot pay you.
If you do not have a recent P45, your employer should ask you to complete HMRC’s Starter Checklist.
Your answers help determine how you should initially be treated for PAYE. Complete it carefully, particularly if you have another job, have received taxable benefits or have already worked elsewhere during the tax year.
What about BR and 0T?
This is where emergency tax can become confusing.
You may hear BR or 0T described as emergency tax when somebody notices an unexpectedly large tax deduction. Strictly speaking, HMRC does not classify BR or 0T by themselves as emergency tax codes.
BR normally means all the income from that employment or pension is being taxed at the basic rate. It is commonly used where somebody has more than one job or pension.
0T means no Personal Allowance is being given against that particular income. It can also be used when you start a new job and your employer does not have enough information to give you another code.
So don’t rely on whether somebody has called it “emergency tax”. Check the actual tax code.
Will HMRC correct it automatically?
Often, yes.
When you start a new job, your employer reports the employment to HMRC. HMRC can then use information from your new and previous employers to decide whether your tax code needs changing.
HMRC advises allowing up to 35 days from starting your new job for the information to update.
You can check your current tax code and the employment information HMRC holds through your Personal Tax Account or the HMRC app.
What if my tax code is still wrong?
If you started your job more than 35 days ago and believe the code is still incorrect, check the information HMRC holds for you.
Look at your current and previous employments, estimated income, pensions and company benefits. It is also worth checking that an old employment has not remained active incorrectly.
Your employer cannot simply choose a different tax code because you think yours is wrong. Payroll must normally use the code HMRC instructs them to use.
Will I get emergency tax back?
If you have paid too much tax, you should not automatically lose the money.
Once HMRC has the information it needs and issues a corrected tax code, an overpayment can often be refunded through your wages or pension.
If it is not corrected during the tax year, HMRC can review your income and tax after the year ends and determine whether a refund is due.
Emergency or incorrect codes can also result in too little tax being deducted. If that happens, HMRC may adjust your code to collect the amount owed.
I’ve got more than one job. Is my tax code wrong?
Not necessarily.
You only have one Personal Allowance, even if you have several jobs or pensions. HMRC therefore needs to decide how that allowance is used between your different sources of income.
One job might use your Personal Allowance while another uses a code such as BR or D0.
That can be completely correct.
The important question is whether HMRC has an accurate picture of your income and has allocated your allowances appropriately.
What should employers do?
Getting the starter information right can prevent problems with an employee’s first payslip.
Use the employee’s P45 where available. If they do not have one, ask them to complete HMRC’s Starter Checklist and use the information provided when setting them up in payroll.
If HMRC subsequently issues a new tax code, payroll records should be updated accordingly.
Not sure whether your tax code is right?
Tax codes can look like a random collection of numbers and letters, but each part has a purpose.
If something on your payslip does not look right, it is worth checking rather than assuming it will eventually sort itself out.
At North Devon Accounts, we can help you understand what your tax code means, identify why it may have changed and work out what needs to happen next.
And if you are an employer, we can help make sure PAYE and payroll are being handled correctly from the start.
Something doesn’t look right on your payslip or payroll? Talk to the NDA team and we’ll help you make sense of it.
