Key facts
- The most common emergency code for 2025/26 is 1257L W1 (weekly) or 1257L M1 (monthly).
- Emergency codes operate on a non-cumulative basis — each pay period is calculated in isolation.
- You can be placed on an emergency code if you start a new job without a P45 or starter checklist.
- Emergency codes are temporary — HMRC will issue the correct code once it has the right information.
- Being on an emergency code can result in overpaying or underpaying tax until it is corrected.
What Is an Emergency Tax Code?
An emergency tax code is a temporary code that HMRC applies when it does not have the information it needs to work out your correct code. It gives you the standard Personal Allowance (£12,570) but calculates tax on a non-cumulative basis, meaning each pay period is treated independently without reference to your year-to-date earnings.[1]
How Emergency Codes Appear
Emergency tax codes for 2025/26 typically look like this on your payslip:
| Code | Pay Frequency | Meaning |
|---|---|---|
| 1257L W1 | Weekly | Standard allowance, non-cumulative (week 1 basis) |
| 1257L M1 | Monthly | Standard allowance, non-cumulative (month 1 basis) |
| 1257L X | Any | Same as W1/M1 — X indicates non-cumulative |
Some payroll systems display the non-cumulative indicator differently — look for W1, M1, or X alongside the number.
Why You Might Be on an Emergency Code
Common reasons include:[1]
- Starting a new job without a P45 — your employer has no record of your previous pay and tax
- Not completing a starter checklist — HMRC cannot determine which statement applies to you
- Starting your first job — HMRC has no previous employment history for you
- Returning to work after a gap — HMRC’s records may be out of date
- Starting a second job — HMRC needs time to adjust codes across both employments
- Receiving a pension for the first time — the pension provider may use an emergency code initially
Impact on Your Pay
On an emergency code, your tax is calculated as if each pay period is the first in the year. This means:[2]
| Scenario | Effect |
|---|---|
| You started mid-year after not working | You may overpay tax because the code does not account for unused allowance from earlier months |
| You have two jobs | You may underpay tax if the emergency code gives you a full allowance that should only apply to one job |
| You earn a consistent monthly salary | The tax deducted each month may be roughly correct, but the annual total may be slightly wrong |
Example: You start a new £30,000/year job in August (month 5) without a P45. On an emergency 1257L M1 code, each month is taxed as if it were month 1. You miss out on the unused Personal Allowance from months 1–4, potentially overpaying by several hundred pounds until the code is corrected.
Getting Your Code Corrected
To resolve an emergency tax code as quickly as possible:[3]
- Give your P45 to your new employer — this is the fastest way to set the right code
- If you do not have a P45, complete the HMRC starter checklist — your employer provides this
- Check your Personal Tax Account at gov.uk/check-income-tax-current-year
- Contact HMRC on 0300 200 3300 if the code has not been corrected within a few weeks
Getting a Refund
If you overpaid tax while on an emergency code:
- During the tax year: Once HMRC issues the correct cumulative code, your employer’s payroll software recalculates your year-to-date tax and refunds the difference through your next pay packet
- After the tax year: If the year has ended, you can claim a refund from HMRC using form P50 or through your Personal Tax Account. HMRC may also issue a P800 tax calculation automatically
Tip: Keep your P45 safe when you leave a job. Providing it to your new employer on your first day is the single most effective way to avoid emergency tax.
Frequently Asked Questions
How do I know if I am on an emergency tax code?
Check your payslip. If your tax code shows 1257L with W1 or M1 after it (sometimes shown as 1257L W1, 1257L M1, or 1257LX), you are on an emergency code. You can also check your tax code through your HMRC Personal Tax Account online.
Will I get a refund if I overpay on an emergency code?
Yes. Once HMRC issues your correct cumulative tax code, your employer’s payroll software will automatically recalculate your tax for the year so far and refund any overpayment through your wages. If the tax year has already ended, you may need to claim a refund from HMRC directly.
How long does an emergency tax code last?
It depends on how quickly HMRC receives the information it needs. If you provide a P45 from your previous employer or complete a starter checklist promptly, HMRC may issue a corrected code within a few weeks. In some cases it can take 2–3 months.
Can I speed up getting the right tax code?
Yes. Make sure your new employer has your P45 or a completed starter checklist. You can also contact HMRC through your Personal Tax Account or by phone (0300 200 3300) to confirm your employment details and request a correct code.
Further Reading
- Cumulative vs Week 1 / Month 1 — understanding non-cumulative tax calculation
- The P45 Process — how P45s prevent emergency tax codes
- Starter Checklists — what to do when a new employee has no P45
- Checking & Correcting Your Tax Code — verifying your code through HMRC
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Sources
- Emergency tax codes — GOV.UK
- Tax codes — GOV.UK
- Check your Income Tax for the current year — GOV.UK