Emergency Tax Code UK 2025: How to Get Your Refund
Last updated: February 2026
Been put on an emergency tax code? You may be overpaying tax on every payslip. This guide explains what emergency tax codes are, why they happen, and exactly how to get every penny of overpaid tax returned to you.
Emergency Tax Overpayment Calculator
Estimate how much tax you may have overpaid on an emergency code compared to your correct code.
What Is Emergency Tax?
Emergency tax is not a special type of tax — it is simply the result of your employer deducting income tax using a temporary, incorrect tax code because HMRC does not yet have the information needed to issue the correct one. The word “emergency” refers to the temporary nature of the code, not a financial emergency.
When HMRC lacks information about your income, they apply a default code to ensure some tax is collected. This is usually more tax than you actually owe, meaning you will typically get a refund once your correct code is applied.
Emergency tax most commonly affects people who:
- Start a new job and do not have a P45 from their previous employer
- Are starting their very first job and have never paid PAYE before
- Return to work after a significant break (e.g., maternity leave, career break, illness)
- Start receiving a pension for the first time (especially a private or workplace pension)
- Have not submitted a Starter Checklist to their new employer
The Three Emergency Tax Codes Explained
There are three codes commonly used as emergency codes in the UK:
1. Code 1257L W1/M1 — Month 1 or Week 1 Basis
This is the most common emergency code. You receive one month's worth of personal allowance (£1,047.50) or one week's worth (£241.73) each pay period, but your tax is calculated independently without accounting for any unused allowance from earlier in the tax year. If you started work in December, for example, you do not benefit from the 8 months of unused allowance from April to November.
2. Code BR — Basic Rate on All Income
BR gives you no personal allowance at all. Every pound you earn is taxed at 20%. This is a significantly worse outcome than 1257L W1/M1 if this is your main job. A person earning £2,500 per month on BR pays £500 in tax, versus approximately £290 with the correct 1257L code — a monthly overpayment of around £210.
3. Code 0T W1/M1 — No Allowance, Non-Cumulative
0T provides no personal allowance and taxes are calculated non-cumulatively. Like BR, it taxes all income, but unlike BR it can apply higher rate (40%) and additional rate (45%) tax on higher slices of income. This is the harshest emergency code and most likely to result in a significant overpayment.
How Month 1 Basis Works: A Step-by-Step Example
Understanding Month 1 basis is crucial to knowing how much you may have overpaid. Here is a worked example:
Scenario: Sophie earns £30,000 per year (£2,500/month). She starts a new job in November (month 8 of the tax year) and is put on code 1257L M1.
| Code Type | Monthly Tax-Free | Monthly Taxable Pay | Monthly Tax (20%) |
|---|---|---|---|
| 1257L M1 (emergency) | £1,047.50 | £1,452.50 | £290.50 |
| 1257L cumulative (correct) | £1,047.50 × 8 = £8,380 cumulative | £2,500 - £8,380 already used = much less | Potentially £0 for several months |
Under the cumulative code, Sophie benefits from the £8,380 of unused personal allowance from April to October. This means her first few months on the correct code may result in almost no tax being deducted, as her employer “catches up” on the tax-free allowance she has been entitled to all year.
How HMRC Corrects Emergency Tax Codes
HMRC operates a Real Time Information (RTI) payroll system. Every time your employer pays you, they electronically notify HMRC of the amount paid and tax deducted. HMRC uses this information, along with your National Insurance number, to match your income to your tax record and issue the correct code.
Employer Submits RTI
Your employer reports your pay and tax to HMRC every payday, usually within the same day.
HMRC Matches Records
HMRC matches your NI number and employment details to your tax record. This typically takes 2-6 weeks.
New Code Issued
HMRC sends an updated tax code electronically to your employer. Your employer must apply the new code from the next payroll run.
Refund via Payslip
Once on the correct cumulative code, your employer automatically refunds any overpaid tax through lower tax deductions or a lump sum on your next payslip.
The entire process typically takes 2 to 3 months from the date you started, provided everything is running smoothly. You can speed it up significantly by taking action yourself.
How to Speed Up Your Emergency Tax Refund
Do not sit and wait for HMRC to fix things automatically. Here are the most effective steps to take immediately:
Step 1: Provide Your P45
Your P45 is the document your previous employer gives you when you leave. It shows your total pay and tax for the year so far. Hand it to your new employer as soon as possible — ideally on your first day. Your employer will enter the P45 data into their payroll system, which triggers HMRC to issue the correct code much faster.
Step 2: Complete the Starter Checklist
If you do not have a P45 (e.g., first job, returning from long break), complete the Starter Checklist accurately. This form asks whether this is:
- Statement A: This is your first job since last 6 April and you have not been receiving benefits or a pension.
- Statement B: This is your only job, but you have had another job or received benefits since last 6 April.
- Statement C: You have another job or receive a pension elsewhere.
Statement A gives you code 1257L from the start. Statement B gives 1257L W1/M1. Statement C gives BR. Choosing the right statement is critical.
Step 3: Contact HMRC Directly
If your code has not been corrected after 2 months, contact HMRC via your Personal Tax Account at gov.uk or by calling 0300 200 3300. Explain that you are on an emergency code and provide your NI number, employer's PAYE reference, and your start date. HMRC can manually issue a new code immediately.
Getting a Refund After the Tax Year: The P800
If the tax year has already ended and you overpaid tax due to an emergency code, HMRC will review your records between September and November of the following year and send you a P800 Tax Calculation. This document shows:
- Your total income for the completed tax year
- The total tax you paid
- The total tax you should have paid
- The amount of refund due (or underpayment to collect)
If your P800 shows a refund, you have two options:
- Claim online: Log in to your HMRC Personal Tax Account and claim the refund. It will be paid directly to your bank account within 5 working days.
- Wait for a cheque: If you do not claim online within 45 days, HMRC automatically sends a cheque to your registered address. This takes approximately 21 days to arrive.
Emergency Tax on Pensions
Emergency tax is particularly common when you first access a pension pot, especially if you take a flexible withdrawal or lump sum under pension freedoms rules. Pension providers apply an emergency tax code (typically 1257L M1 or, in many cases, the full monthly 0T M1 code) to the first payment because they do not yet have your correct PAYE code.
This can result in a substantial overpayment. For example, if you withdraw £20,000 from a pension in a single month, HMRC's system may treat this as if you earn £240,000 per year and tax accordingly — at 45% on much of it.
To reclaim emergency tax on a pension payment, you can use one of three HMRC forms:
- P55: Claim back overpaid tax on a partial pension withdrawal when you have not emptied the pot
- P53Z: Claim back overpaid tax when you have emptied a pension pot and have other income
- P50Z: Claim back overpaid tax when you have emptied a pension pot and have no other income
These forms can be submitted online via HMRC's website or by post. HMRC aims to process them within 30 days.
Frequently Asked Questions
What is emergency tax in the UK?+
Emergency tax is a temporary, usually incorrect tax deduction applied when HMRC lacks the information to issue your correct tax code. It most commonly affects new starters, first-time employees, and people returning to work. You are nearly always owed a refund when on an emergency code as your main job.
How much extra tax do I pay on an emergency code?+
On 1257L W1/M1, you receive only one month's allowance per month rather than benefiting from the full year's unused allowance. On BR, you pay 20% on every pound with no free allowance. On a £25,000 salary starting in December, you could overpay up to £1,000 in that tax year.
How long does it take HMRC to correct an emergency code?+
Usually 2 to 3 months automatically. Providing your P45 to your new employer or completing the Starter Checklist correctly typically reduces this to 2 to 6 weeks. Contacting HMRC directly can result in immediate correction.
What is the Starter Checklist and do I need one?+
The Starter Checklist (formerly P46) is completed when you start a new job without a P45. It helps your employer assign the right initial tax code. Complete it honestly: incorrect statements (especially claiming Statement A when B or C applies) can result in underpayment of tax, which HMRC will collect later.
Can I claim emergency tax back for previous years?+
Yes. You can claim overpaid tax going back 4 tax years. HMRC usually identifies this and sends a P800 automatically. If you do not receive one, log in to your HMRC Personal Tax Account or call 0300 200 3300. Never use a tax refund company — they charge 30-40% commission for free work.
What if my employer refuses to change my tax code?+
Your employer is legally required to apply the tax code HMRC issues. If HMRC sends your employer an updated code and they do not apply it, report this to HMRC. In the meantime, you can write to HMRC requesting your correct code and they will contact your employer directly. Do not stop the process by assuming your employer will sort it.
What is the difference between 1257L W1/M1 and BR emergency codes?+
1257L W1/M1 gives you one period's personal allowance each pay period but does not accumulate unused allowance. BR gives no personal allowance at all. For a typical salary, BR results in more overpaid tax than 1257L W1/M1. Both are fully refundable once your correct code is applied.