What Does the 1257L W1 Tax Code Mean?
Week 1 Emergency Code
description Core Meaning & Overview
A weekly emergency code telling your employer to calculate tax strictly on each week’s pay in isolation, without looking at your total year-to-date earnings.
account_balance Legal & Payroll Mechanics (2026/27)
HMRC applies the W1 suffix when they do not have your cumulative year-to-date figures from your previous employment. You receive 1/52nd of your Personal Allowance (£241.73) each week. Because it is non-cumulative, previous overpayments or underpayments cannot automatically balance out.
warning Is Your 1257L W1 Tax Code Correct?
Submit your P45 from your previous employer to payroll, or verify your employment history in the HMRC app so HMRC can update you to standard cumulative 1257L.
help Frequently Asked Questions About 1257L W1
Why am I on 1257L W1?
You started a new job without a P45, or HMRC has not received full payroll checkout figures from your former employer.
Will I get overpaid tax back once W1 is removed?
Yes. As soon as HMRC switches your code back to cumulative 1257L, your employer’s payroll software will automatically calculate the full-year position and refund any excess tax.