To get off an emergency tax code, give your employer a P45 or completed Starter Checklist, or update your details with HMRC through your Personal Tax Account or the Income Tax helpline. Once HMRC has the missing information, it issues a corrected code to your employer and any tax you overpaid comes back through your pay or, after the tax year ends, in a P800 refund.
Check That You’re On an Emergency Code
Look at your payslip. An emergency code carries a suffix of W1 (weekly pay), M1 (monthly pay), or X (irregular pay dates) after the number.1GOV.UK. Tax Codes: Emergency Tax Codes For 2026–27 the number is usually 1257L, matching the £12,570 personal allowance,2GOV.UK. Income Tax Rates and Allowances for Current and Previous Tax Years so 1257L W1 or 1257L M1 on the payslip confirms it.
The code taxes each pay period on its own instead of spreading your allowance across the year. That’s why you usually end up paying more than you owe: any unused allowance from earlier months isn’t credited back until the code is corrected.
The trigger is normally missing information. Starting a new job without a P45, moving from self-employment into PAYE, beginning a company pension, or taking a second job can all leave HMRC without a full picture of your earnings.3GOV.UK. Tax Codes: Why Your Tax Code Might Change Delays updating taxable state benefits such as Jobseeker’s Allowance, Employment and Support Allowance, or Incapacity Benefit can do the same.4GOV.UK. Income Tax: Tax-Free and Taxable State Benefits
Fix It Through Your Employer
This is usually the fastest route. If you have a P45 from your previous job, hand it to your new employer’s payroll team straight away. The P45 shows your pay and tax so far this year, which is what payroll needs to move you onto a cumulative code.
No P45? Fill in a Starter Checklist. You pick one of three statements, and this is where people get stuck:5GOV.UK. Starter Checklist for Employees
- Statement A applies if this is your first job since 6 April and you haven’t received Jobseeker’s Allowance, Employment and Support Allowance, or Incapacity Benefit. Your employer applies your full personal allowance cumulatively, and you’re on a normal code from day one.
- Statement B applies if you’ve had another job since 6 April but don’t have the P45, or if you’ve received one of those benefits. Your employer applies the allowance on a week 1/month 1 basis until HMRC corrects it.
- Statement C applies if you have another job or receive a state, workplace, or private pension alongside this one. Your employer uses the BR code, taxing everything at the basic rate with no allowance.
Ticking B or C when A actually applies to you keeps you on an emergency or basic-rate code longer than necessary.6HM Revenue and Customs. Starter Checklist Read the statements carefully before you sign.
Most payroll departments work to a cutoff around the 15th to 20th of the month. Get the paperwork in before then, or the correction slips into the next pay cycle.
Fix It Through HMRC
If your employer already has your details but the code hasn’t caught up, deal with HMRC directly.
Online, Through Your Personal Tax Account
Sign in to your Personal Tax Account on GOV.UK and open “Check your Income Tax.” You can view your current code, see recent changes, and tell HMRC about a new job, updated income estimate, or change in benefits.7GOV.UK. Check Your Income Tax for the Current Year Once you update your details, HMRC recalculates the code and sends the new one electronically to your employer.
You’ll need a Government Gateway account. If you haven’t used one before, verifying your identity may take photo ID such as a passport or driving licence. One caveat: if Self Assessment is the only route through which you pay Income Tax, this service won’t let you check your current-year code.
By Phone
Call the HMRC Income Tax helpline on 0300 200 3300. Before you dial, have your National Insurance number, your employer’s name and PAYE reference, and any figures for previous income in the tax year. Your most recent payslip with year-to-date totals, or last year’s P60, helps.
Say clearly that you’re on an emergency tax code and need it corrected. The advisor can override the code and send the corrected one to your employer.
Getting Your Overpaid Tax Back
If the Code Is Corrected Before 5 April
Once HMRC issues the new code, your employer applies it on your next payday if you’re paid monthly, or within three pay periods if you’re paid weekly.8GOV.UK. Tax Codes: If You’ve Paid Too Much or Too Little Tax Because the new code is cumulative, payroll recalculates the whole year and any overpayment lands in that payslip as extra take-home pay. No separate claim is needed.
If the Tax Year Ends First
If 5 April passes before the code is fixed, HMRC reviews the year and, if you’ve overpaid, sends a P800 tax calculation letter. What you do next depends on which version arrives:9GOV.UK. Tax Overpayments and Underpayments: If Your Tax Calculation Letter (P800) Says You’re Due a Refund
- If the P800 says you can claim online, you have to act. Log in to the GOV.UK service with the reference number on the letter and your National Insurance number, then pick a bank transfer (usually within five working days) or a cheque. Ignore it and the refund sits on your tax record until you claim.
- If the P800 says you’ll get a cheque, HMRC sends it automatically by post. Nothing for you to do.
P800 letters generally arrive in the summer or autumn after the tax year ends, so a quiet April and May are normal.
How Quickly It All Happens
If you hand over a P45 or a correctly completed Starter Checklist as soon as you start a job, an emergency code can clear within one pay cycle. Contacting HMRC directly works on a similar timeline, with the corrected deductions showing on your next payday.
The longer you leave it, the more overpaid tax accumulates. You’ll get it back eventually, but sorting the code out early keeps the money in your account rather than HMRC’s. Check the next payslip after you act to confirm the W1, M1, or X has gone.