Emergency Tax Codes Explained: BR, 0T, W1/M1 and How to Get a Refund (2026)

An "emergency" tax code is not a penalty and it does not mean you have done anything wrong. It is simply the code HMRC or your employer uses as a stop-gap when they do not yet have a complete picture of your income and allowances — most often when you start a new job without a P45, take money from a pension, or start work for the first time.

The problem is that emergency codes are deliberately cautious, so they usually take too much tax. Here is what each one means and how to fix it.

What each emergency code means

• —1257L W1/M1 (or X): you get your normal tax-free allowance, but on a "non-cumulative" basis — each pay period is taxed in isolation, ignoring what you have already earned and paid this year. Often results in small over- or under-payments that reconcile later.
• —BR: "Basic Rate". All income from this job or pension is taxed at 20%, with no tax-free allowance applied. Common on a second job — but if your allowance is not being used elsewhere, you are overpaying.
• —D0: all income taxed at the higher rate of 40%. D1 taxes everything at the additional rate of 45%.
• —0T: no Personal Allowance at all, and tax charged at the rate for each band. Used when your employer has no details and you have used your allowance elsewhere — frequently over-taxes new starters.
• —K codes: not strictly emergency codes, but a K prefix means you have income or a deduction (such as a company benefit) greater than your allowance, so extra tax is collected.

Why you were put on one

The usual triggers are: starting a new job without handing your new employer a P45; starting your first-ever job; having a second job or pension alongside your main income; taking a flexible lump sum from a pension; or a gap where HMRC lost track of your income. In each case the system applies a safe-but-blunt code until your real details catch up.

How to get off emergency tax and claim a refund

• —Give your employer your P45 from your previous job, or complete the new-starter checklist so they can request the correct code.
• —Check your Personal Tax Account on GOV.UK — you can often see and correct the code, and add missing income sources.
• —Once the correct cumulative code is applied, any overpaid tax is usually refunded automatically through your next payslip in the same tax year.
• —If the year has already ended, you claim the overpayment back via a P800 or directly through your tax account — and you can go back four tax years.