Emergency Tax Code Explained: How to Spot and Fix It
Emergency tax code explained. Find out what 1257L W1/M1/X means, why you are overpaying tax, and how to claim a refund from HMRC in 2026.
You start a new job. Your first payslip arrives. The number is much lower than you expected. You look at the tax code section. It says 1257L W1. Or 1257L M1. Or simply BR. This is an emergency tax code.
An emergency tax code is a temporary code that HMRC uses when it does not have enough information about your employment history or income. Under an emergency tax code, your employer deducts tax based only on your pay in that specific week or month, without considering how much you have earned earlier in the tax year.
The emergency tax code for 2026/27 is 1257L. But an emergency code always includes a suffix: W1 (weekly), M1 (monthly), or X (irregular pay periods). These suffixes tell your payroll department not to use cumulative tax calculations. Understanding emergency tax codes can save you from overpaying HMRC by hundreds of pounds.
This guide explains what emergency tax codes mean, why you have one, how they affect your pay, and how to fix them and claim a refund.
Use our Income Tax Calculator to check your take-home pay and identify potential overpayments.
For a detailed breakdown of the standard tax code, our 1257L tax code guide explains how the normal code works.
An emergency tax code is a temporary code HMRC uses when it lacks full income information. For 2026/27, the emergency code is 1257L with W1, M1, or X suffix. These codes almost always result in overpaying tax.
What Is an Emergency Tax Code
The standard tax code for most UK employees at the time of writing is 1257L. The number 1257 represents your Personal Allowance of £12,570. The letter L means you are entitled to this standard allowance.
An emergency tax code uses the same numbers but adds a suffix: W1, M1, or X. For example, 1257L W1 applies if you are paid weekly. 1257L M1 applies if you are paid monthly. 1257L X applies for irregular pay periods.
Under a normal cumulative tax code, your employer calculates tax based on your total earnings from the start of the tax year, which runs from 6 April to 5 April. Under an emergency code with W1, M1, or X, your employer calculates tax only on that specific week or month in isolation.
This means you do not benefit from your full annual Personal Allowance unless you work the entire tax year. If you start a job halfway through the year, you could end up paying tax on income that should be tax-free.
What is an emergency tax code? It is a temporary code (1257L W1, 1257L M1, or 1257L X) that calculates tax on a non-cumulative basis, treating each pay period separately.
Common Emergency Tax Codes Explained
Emergency tax codes can appear in several forms. Some are obvious emergencies. Others are permanent emergency-style codes.
| Tax Code | Meaning | Typical Situation |
|---|---|---|
| 1257L W1 | Weekly emergency | New job without P45 |
| 1257L M1 | Monthly emergency | New job without P45 |
| 1257L X | Non-standard period | Irregular pay |
| BR | All income at 20% | Second job |
| 0T | No allowance, taxed at bands | New job, no P45 |
| D0 | All income at 40% | Second job, higher earner |
| D1 | All income at 45% | Second job, additional rate |
| T | HMRC other calculations | Underpayments or benefits |
Tax code 0T means you have no Personal Allowance applied. This happens when you start a new job without providing a P45 or starter checklist, and HMRC has not yet issued a proper code.
BR stands for Basic Rate. Your employer deducts 20% tax from all earnings from that job, with no tax-free allowance. This is common for second jobs where your Personal Allowance is already used against your main income.
For a complete list of tax codes, the list of UK tax codes covers every code you might see on your payslip.
Common emergency tax codes include 1257L W1/M1/X (temporary), BR (basic rate, no allowance), and 0T (no allowance, tax at all bands).
Why You Have Been Given an Emergency Tax Code
Emergency tax codes happen for several practical reasons. In most cases, HMRC simply does not have enough information about your income yet.
Starting a new job without a P45. When you leave a job, your employer gives you a P45. If you do not give this to your new employer, they cannot see how much you have already earned or paid in tax. Without this information, they must use an emergency tax code.
Returning to work after a break. If you were not working and then start a new job, you may not have a recent P45. Your employer will use an emergency code until HMRC confirms your correct code.
Agency or temporary work. Agency workers often change assignments frequently. Each new assignment may trigger an emergency code if the agency does not have your full employment history.
Working multiple jobs. HMRC allocates your Personal Allowance to one job. Your other jobs will typically receive a BR code, meaning no tax-free allowance is applied. See our second job tax guide for more details.
Taking money from your pension. When you make your first withdrawal from a pension, the provider usually applies an emergency tax code. HMRC treats this as a regular monthly income even if it is a one-off payment.
In practice, many employees discover they are on an emergency tax code only when their first payslip is much lower than expected. A frequent payroll issue is that temporary summer jobs or short-term contracts often result in emergency codes.
Emergency tax codes typically occur when starting a new job without a P45, working through an agency, taking first pension withdrawals, or having multiple jobs.
How an Emergency Tax Code Affects Your Pay
An emergency tax code almost always reduces your take-home pay. In some cases, the reduction is significant.
Consider a worker who starts a new job in October, halfway through the tax year. Their monthly salary is £2,500. Under a normal cumulative tax code, they have earned £0 so far. Their cumulative Personal Allowance of £12,570 means they will pay no tax on the first several months. Their take-home pay for October would be close to £2,500.
Under an emergency tax code (1257L M1), the employer calculates tax only on October's pay, using 1/12th of the Personal Allowance (£1,048). Taxable pay is £1,452. At 20%, that is £290 tax. Take-home pay is approximately £2,210 – about £290 less than it should be.
If this worker only works four months in the tax year, total earnings would be £10,000. That is below the Personal Allowance of £12,570. They should pay zero tax. But under an emergency code, they would have paid over £1,000 in tax.
Many people end up on emergency tax codes every year, particularly those with temporary or summer jobs. If you are affected, our overpaid tax guide explains your options.
An emergency tax code typically reduces take-home pay because you do not receive your full annual Personal Allowance proportionally, causing significant overpayments for part-year workers.
How to Check Whether Your Tax Code Is Wrong
You cannot fix an emergency tax code unless you know you have one. Checking takes only a few minutes.
Step 1: Find your payslip. Your tax code is clearly displayed. It will look like 1257L, 1257L W1, 1257L M1, BR, or 0T.
Step 2: Look for emergency indicators. If your code ends with W1, M1, or X, you are on an emergency tax code. If your code is BR, 0T, D0, or D1 on your main job, you may also be overpaying tax.
Step 3: Check your HMRC Personal Tax Account. Create or log into your Government Gateway account at GOV.UK. You can see your current tax code, your estimated income, and your tax calculation.
Step 4: Verify your employment details. Check that HMRC has the correct start date, estimated annual income, and correct details for any other jobs or pensions.
In practice, many employees do not realise their tax code is wrong until they compare their payslip to a colleague's or use an online tax calculator.
How to check tax code: Look for W1, M1, X, BR, or 0T on your payslip. Log into your HMRC Personal Tax Account online. Verify your employment details are correct.
How to Fix an Emergency Tax Code
Fixing an emergency tax code is straightforward once you know you have one.
Step 1: Provide your P45 to your employer. If you have a P45 from your previous job, give it to your new employer as soon as possible. They will update your payroll record.
Step 2: Complete a starter checklist. If you do not have a P45, complete a starter checklist for your employer. This form asks about your employment history. Based on your answers, your employer can apply a more appropriate temporary code.
Step 3: Contact HMRC directly. The fastest way to resolve an emergency tax code is often to contact HMRC yourself. Log into your Personal Tax Account online or call HMRC's PAYE helpline on 0300 200 3300.
Step 4: HMRC will issue a new tax code. Once HMRC has the correct information, they will send your employer an updated tax code. Your employer must apply this to your next payroll run.
How long does correction take? If you contact HMRC directly, they often issue a new code within a few days. Your employer should apply it in the next payroll cycle.
The how to check and correct your HMRC tax code guide covers the process in full.
How to fix an emergency tax code: Provide your P45 or complete a starter checklist. Contact HMRC directly via your Personal Tax Account or call 0300 200 3300.
Emergency Tax Refunds Explained
If you have been on an emergency tax code, you have almost certainly overpaid tax. You are entitled to a refund.
Automatic refund via PAYE. Once HMRC issues a correct cumulative tax code, your employer will adjust your future payslips. They will deduct less tax (or even negative tax) until the overpayment is fully refunded.
Refund after the tax year ends. If you do not get a correction during the tax year, HMRC will automatically reconcile your tax position after 5 April. They will send you a tax calculation (P800) and issue a refund.
Claim refund from HMRC directly. If you need the money sooner, contact HMRC. Calling 0300 200 3300 or using your Personal Tax Account is usually faster than waiting for an automatic refund.
How far back can you claim? You can claim overpaid tax for up to four previous tax years. At the time of writing, you can go back to 2021/22.
Our step-by-step tax refund guide explains how to claim your money back.
Emergency tax refunds are paid automatically through your payslip once your code is corrected, or after the tax year ends. You can also claim proactively by contacting HMRC.
Emergency Tax on Pension Withdrawals
Emergency tax is extremely common on first pension withdrawals. Thousands of people overpay tax on pension lump sums every year.
Why does this happen? When you take your first taxable pension withdrawal, your provider does not know your total income for the year. HMRC requires them to use an emergency tax code on a month 1 (M1) basis.
The provider treats your withdrawal as if you will receive the same amount every month. For example, a one-off withdrawal of £30,000 is treated as an annual income of £360,000. This pushes you into higher tax brackets for that single payment.
If this is their only income for the year, they should pay much less tax. They can reclaim the overpayment using form P55 (partial withdrawal) or P50Z (full withdrawal with no other income).
Our pension tax calculator can help you estimate how much tax should have applied to your pension withdrawal.
Emergency tax on pension withdrawals is common. Providers treat one-off withdrawals as regular monthly income. Claim refunds using form P55, P50Z, or P53Z.
Emergency Tax and Multiple Jobs
Having more than one job frequently causes tax code confusion.
HMRC can only apply your Personal Allowance to one job at a time. Your main job should receive the full allowance (code 1257L). Your second job will typically receive a BR code (Basic Rate, all earnings taxed at 20%).
Problems arise when HMRC does not know which job is your main job. Your second job might incorrectly receive your Personal Allowance, leaving your main job on BR or 0T. This results in underpaying tax on the main job and overpaying on the second.
To fix this, log into your Personal Tax Account and tell HMRC which job is your main job. You can also adjust your estimated annual income for each job. HMRC will then reallocate your Personal Allowance appropriately.
Contractors and agency workers are particularly vulnerable. Each new assignment may create a new PAYE record, leading to repeated emergency codes.
Having multiple jobs often results in BR codes on second jobs. Ensure HMRC knows which job is your main job to receive your full Personal Allowance.
Common Emergency Tax Mistakes
Many workers overpay tax unnecessarily because of simple, avoidable mistakes.
Not providing a P45 to your new employer. This is the number one reason for emergency tax codes. Even if you do not have a P45, completing a starter checklist is essential.
Ignoring HMRC letters. HMRC sends tax code notices. Many people throw them away without reading. These letters contain your tax code and instructions for how to correct it.
Not checking payslips. Most employees never look at their tax code. They only notice when their pay drops significantly.
Assuming your employer will fix it automatically. Employers can only use the information they have. If you do not give them a P45 or complete a starter checklist, they must use an emergency code.
One of the most common mistakes is assuming that temporary work does not count towards your Personal Allowance. If you work a summer job and pay emergency tax, you may be due a significant refund – but only if you claim it.
Our PAYE payslip guide helps you understand what each line on your payslip means.
Common mistakes include not providing a P45, ignoring HMRC letters, not checking payslips, and assuming employers will automatically fix errors.
When to Contact HMRC
While many tax code issues resolve themselves once you provide correct information, some situations require you to contact HMRC directly.
Contact HMRC immediately if: you have been on an emergency tax code for more than two months, your tax code is BR on your main job, you have multiple jobs and HMRC allocated your Allowance to the wrong one, you are about to take a pension withdrawal, or you receive a tax calculation showing an unexpected underpayment or overpayment.
How to contact HMRC: Online via your Personal Tax Account, by phone on 0300 200 3300, or through webchat in your Personal Tax Account.
The fastest way to resolve urgent payroll tax issues is to call HMRC. Have your National Insurance number and recent payslip ready. HMRC can issue a new tax code to your employer while you are on the phone in some cases.
If you have overpaid tax and need the money urgently, ask HMRC to process a repayment rather than waiting for it to come through your payslip.
Contact HMRC if you have been on an emergency code for over two months, your main job has a BR code, or you have complex pension or multiple job situations.
Final Thoughts
An emergency tax code is not permanent, but it can cost you hundreds or even thousands of pounds if you leave it uncorrected. The emergency tax code for 2026/27 is 1257L with a W1, M1, or X suffix.
If you see any of these codes on your payslip, take action. Provide your P45 or complete a starter checklist. Log into your HMRC Personal Tax Account and verify your details. Call HMRC if you need a faster resolution.
Refunds for overpaid tax are available. You can claim overpayments for up to four previous tax years. If you have taken a pension withdrawal and were hit by emergency tax, use form P55, P50Z, or P53Z to claim your refund.
The strongest advice is simple: check your payslip every month. Check your tax code after every job change. A few minutes of attention can save you from overpaying tax unnecessarily.
All information in this guide is based on official HMRC and GOV.UK sources. Readers should verify their tax code through their HMRC Personal Tax Account before making financial decisions, as individual circumstances vary and rules may change after publication.
Written by
Daniel Reed
Daniel Reed writes about PAYE, payslips, tax codes, workplace deductions and take-home pay in the UK.
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