Answers · UK 2025/26
How do I reclaim tax paid under an emergency tax code?
If you have been taxed under an emergency code such as 1257L W1/M1 or 0T, you can reclaim overpaid tax by contacting HMRC, filing a Self Assessment return, or updating your tax code via the HMRC app.
Full answer
Emergency tax codes are applied when HMRC does not have enough information about your income, typically when you start a new job or begin receiving a pension for the first time. Common emergency codes include 1257L W1/M1 which taxes each pay period in isolation ignoring the cumulative allowance, and 0T which gives no personal allowance at all. If you have overpaid tax, HMRC should automatically issue a refund after the end of the tax year via form P800. However, you can speed up the process by calling HMRC, using the HMRC app or your Personal Tax Account online, or submitting a Self Assessment return. Providing your P45 from your previous employer to your new employer at the start of employment is the best way to avoid being placed on an emergency code.
This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.