To stop emergency tax, give your new employer your P45 from your last job, or if you don’t have one, complete the Starter Checklist they provide. If neither route is open to you, sign in to HMRC’s online tax service and update your income details directly. Once HMRC has enough information to work out your correct code, they issue it to your employer, usually within 15 working days, and any tax you’ve overpaid gets refunded automatically through your next payslip.
Check That You’re Actually on an Emergency Code
Look at your payslip. The standard code for 2026/27 is 1257L, which reflects the £12,570 Personal Allowance. That code on its own is not an emergency code. It becomes one when followed by W1, M1, or X.1GOV.UK. Understanding Your Employees Tax Codes Some payroll systems show “NONCUM” instead, which means the same thing.2GOV.UK. Tax Codes – What Your Tax Code Means
Two other codes cause similar problems. A 0T code gives you no tax-free allowance at all, either because HMRC has used your allowance against other income or because your employer doesn’t have enough information to assign a proper code.2GOV.UK. Tax Codes – What Your Tax Code Means A BR code taxes everything from that job at 20% with no allowance, which HMRC typically applies to second jobs or where your situation is unclear. If you see any of these on a single main job, the fix below applies to you.
Hand Over a P45 or Complete the Starter Checklist
The most common reason people end up on emergency tax is starting a new job without giving the employer a P45. The P45 tells your new employer what you’ve earned and what tax you’ve paid so far this tax year. Without it, they have no choice but to use an emergency code.3GOV.UK. Tax Codes – Emergency Tax Codes If you still have your P45 from your previous job, give parts 2 and 3 to your new employer as soon as you can.
If you don’t have a P45, your employer should give you a Starter Checklist. Getting this form right is the single most effective thing you can do.4HM Revenue and Customs. Starter Checklist
The part that trips people up is the statement at the end. There are three options, and the wrong choice can keep you on the wrong code for months:
- 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 this tax year. It gives you the full Personal Allowance on a cumulative basis.
- Statement B applies if you’ve had another job that has ended since 6 April, or you’ve received taxable state benefits. It gives you the Personal Allowance but on a W1/M1 basis until HMRC updates your record.
- Statement C applies if you have another job or receive a pension. It assigns a BR code, taxing all income from this job at 20% with no allowance.
People with only one job sometimes tick Statement C because they aren’t sure, and lose their entire Personal Allowance on that employment. If this job is your only source of income and you haven’t worked since April, Statement A is almost certainly the right choice. The form also asks about student loans, so have your plan type ready (Plan 1, Plan 2, Plan 4, or Postgraduate) if one applies.4HM Revenue and Customs. Starter Checklist
Update Your Details Directly With HMRC
Online
The quickest route on your end is HMRC’s Check your Income Tax service, which sits inside your Personal Tax Account. Once signed in, you can review the estimated income HMRC holds for each of your jobs and pensions, correct anything wrong, and flag changes that affect your code.5GOV.UK. Check Your Income Tax for the Current Year You’ll need a Government Gateway account, which requires your National Insurance number, a valid UK passport or a recent payslip, and a mobile number for two-step verification.6GOV.UK. Personal Tax Account – Sign In or Set Up
Be accurate with your income estimate. If you’re partway through the tax year, base your figure on your current pay rate scaled to the full year. HMRC uses that number to set the code, so a rough guess can leave you paying too much or too little.
By Phone
If you can’t use the online service, call HMRC’s Income Tax helpline. Have your National Insurance number, your employer’s PAYE reference (on your payslip or P60, typically formatted like 123/AB456), and details of your income to hand.7HM Revenue and Customs. Employer PAYE Reference The agent verifies your identity and updates your record manually. Wait times swing widely, so early morning midweek tends to be quickest.
What Happens Once HMRC Has Your Information
HMRC updates your tax code and notifies both you and your employer, usually within 15 working days.8GOV.UK. Tax Codes – If You Think Your Tax Code Is Wrong You get a P2 Notice of Coding, which shows how the new code was worked out and lists the allowances and deductions in it.9HM Revenue and Customs. PAYE Manual – PAYE11030 – P2 Notice of Coding Your employer gets a separate notification with the code to apply.
When your employer moves you from a W1/M1 code to a cumulative one, payroll recalculates your tax for the whole year so far. It looks at everything you’ve earned since 6 April, works out what you should have paid, and compares that to what actually came out of your pay. If you’ve overpaid, the difference comes back in your next payslip, sometimes making it noticeably larger.10HM Revenue and Customs. PAYE Manual – PAYE11090 – Codes: Ways an Employer Can Operate a Code
This is why speed matters. Fix the code early in the tax year and the refund comes through payroll automatically. Leave it too late and you may end up waiting for a separate reconciliation after the year ends.
Getting Money Back If Payroll Can’t Refund You
Most people don’t need to claim anything. Once the cumulative code is in place, your employer’s system handles the refund over the next pay run or two.
If the tax year has ended, or you’ve left the job and payroll can’t pay you back, HMRC reconciles your account and sends either a P800 tax calculation or a Simple Assessment letter. These go out between June and March of the year following the tax year in question.11GOV.UK. Tax Overpayments and Underpayments If your P800 shows an overpayment, claim the refund online through HMRC’s bank transfer service using your National Insurance number and the reference on the letter. Online claims are usually paid within five working days.
A Simple Assessment is issued in different circumstances, such as owing HMRC £3,000 or more or needing to pay tax on your State Pension.12GOV.UK. Check Your Simple Assessment Tax Bill If it shows you’re owed money, the letter tells you how to claim.
If you think you’ve overpaid but no letter has arrived, request a review through your Personal Tax Account or by calling HMRC. Manual reconciliation takes several weeks.
The Four-Year Deadline
You have four years from the end of the tax year to claim overpaid income tax back. For 2025/26, that means 5 April 2030. Miss the window and the money is gone. If you were on an emergency code in a previous year and never checked, log in to your Personal Tax Account and review your records before that clock runs out.