What is an emergency tax code (and how do I get my money back)?

What a normal tax code looks like

Most people with one job have the tax code 1257L. The number is your tax-free Personal Allowance with the last digit knocked off: £12,570 for 2026/27. The L just means you get the standard allowance. Your employer uses the code to work out how much Income Tax to take each payday. If you want the full decoder ring, our lesson Tax codes decoded has it.

So what makes a code an "emergency" one?

When you start a new job and your employer doesn't have the full picture of what you've earned this tax year, HMRC hasn't caught up yet. So payroll uses a holding code. GOV.UK says you can spot one because it ends in:

• W1 if you're paid weekly, for example 1257L W1
• M1 if you're paid monthly, for example 1257L M1
• X if your pay dates vary

These "week 1" or "month 1" codes treat every payday as if it's the first of the tax year. You get one week's or one month's slice of your allowance (about £242 a week or £1,048 a month) but none of the allowance you'd have built up in earlier months. If you've had a quiet few months, that means you can pay more tax than you need to.

The scarier cousins: 0T and BR

Two other codes often turn up when payroll doesn't have your details:

• 0T means you get no tax-free allowance at all from this job. Every pound is taxed.
• BR means everything from this job is taxed at the basic rate of 20%. It's the normal code for a second job, but it's wrong if this is your only job.

Here's how much difference it makes. Say you earn £2,000 in a month. On 1257L M1 you'd pay about £190.50 in Income Tax. On 0T you'd pay about £400. Same job, same pay, more than double the tax. That's the jump scare, and our lesson Emergency tax: the jump scare lets you play through it.

Why you got one

The usual reasons:

• You didn't hand your new employer a P45 from your last job.
• You filled in the starter checklist without ticking the statement that matches you, or left it blank.
• It's your first job ever, so HMRC has nothing on file yet.
• You started a second job (BR is normal there, as long as your main job has the 1257L).

How to fix it

1. Give your employer your P45 if you have one. It tells them what you've earned and paid so far this tax year. Lost it? Your old employer can't issue another, but the starter checklist does the same job. More on the paperwork in P45, P60 and the paperwork tier list. 2. Check your code in the HMRC app or your personal tax account. It shows the code each employer is using. 3. Wait a few weeks. GOV.UK says HMRC usually updates your tax code within 35 days. 4. Still wrong after that? Contact HMRC yourself and update your details. Don't rely on payroll to chase it.

Getting the overpaid tax back

Once your code is corrected (and the W1/M1 bit is removed), your employer normally refunds what you overpaid through your next payslip. If you've left that job, or the tax year has ended, HMRC sorts it out: you can claim through the HMRC app or your personal tax account. You never need to pay a company to claim a tax refund for you, and HMRC never texts you a link to "claim your refund now". That one is Ronnie, our resident scammer, and he's covered in Tax refunds (and Ronnie's 'refunds').

Scotland and Wales

The bit to remember

An emergency code is a placeholder, not a punishment. Hand over your P45 or fill in the starter checklist properly, check your code in the HMRC app, and any overpaid tax comes back. Want the full tour of your payslip? The work and tax library has it.