Emergency Tax Codes Explained

What is emergency tax?

Emergency tax is a temporary PAYE calculation used when the employer or HMRC does not yet have all the income and tax details needed to apply a normal cumulative code. The calculation may treat the current week or month as if it continues for the rest of the tax year.

This can mean the amount deducted is not the amount that would apply once HMRC has complete information. It does not necessarily mean you have done anything wrong.

Which codes are emergency tax codes?

The emergency marker is normally shown at the end of a tax code. Common examples include 1257L W1, 1257L M1 and 1257L X. Your payslip may also show NONCUM, depending on the payroll software used by your employer.

• W1 — week 1: used when you are paid weekly
• M1 — month 1: used when you are paid monthly
• X — used where pay dates vary
• NONCUM — another way an employer may show non-cumulative treatment

Why can emergency tax happen?

Emergency tax can happen when you start a new job and your new employer does not yet have your P45 or enough information about your previous pay and tax. It can also appear when you begin receiving a pension or taxable benefit and HMRC is still updating the records.

Your employer normally reports the new employment to HMRC. HMRC may then update the code once it has the information from your previous and current sources.

What should I do if I am on an emergency code?

Give your new employer your P45 if you have one. Check your HMRC Personal Tax Account to make sure your employment, previous pay and benefits information is correct, and update HMRC if anything is missing.

Do not promise yourself a particular correction date: the timing depends on when HMRC receives and processes the relevant information. If HMRC issues a new code, payroll normally applies it to a later payment.

Is emergency tax always wrong?

No. It can be a reasonable temporary treatment while HMRC gathers information. It can still result in too much or too little tax being deducted at first, which is why checking the code and the underlying details matters.

A code such as 1257L without an emergency marker is different from 1257L W1 or 1257L M1. Codes such as BR and D0 also have different meanings.