What does the 1257L M1 tax code mean?
1257L M1 means: Tax-free allowance of about £12,570.00 a year. In short: the standard allowance on an emergency, non-cumulative basis. A UK tax code is the instruction HMRC sends your employer for the 2026/27 tax year (6 April 2026 to 5 April 2027): it sets how much of your pay is tax-free before income tax is deducted through PAYE, so the code on your payslip directly decides your take-home. The standard code for most employees with one job is 1257L, worth £12,570 of tax-free income a year, any other code should have a reason behind it (a company benefit, a second job, an HMRC adjustment), and a code that's wrong for your situation means paying the wrong tax every single payday until it's fixed. Decoded below against HMRC's rules as checked on 2026-08-28, with what 1257L M1 costs or saves against the standard code.
Decoded
- L: you get the standard personal allowance.
- M1: emergency (non-cumulative). each payday is taxed on its own, ignoring the year so far. Common after starting a new job. It usually rights itself, but check it does not persist past a couple of paydays.
- ⚠ Emergency codes often mean too much tax short-term. HMRC refunds it through your pay once the correct code arrives.
Emergency tax calculator
The checker below doubles as an emergency tax calculator: enter 1257L M1 and then plain 1257L to see the difference the emergency flag makes to a payday. The M1 code gives each month exactly one twelfth of the £12,570 allowance and one twelfth of each band with no catch-up, so if you started work part-way through the year, the allowance for the months before you started is never given to you — that is the overpayment.
Is 1257L M1 an emergency tax code?
Yes. The M1 suffix (like W1 and X) marks the code as emergency, non-cumulative: the allowance is the standard one, but each payday is taxed in isolation instead of being corrected against the year so far. It normally appears after a job change and should clear within a couple of paydays.
How do I get off 1257L M1?
Give your employer your P45 from the last job, or a completed starter checklist if you do not have one, and check your details in your personal tax account on gov.uk. Once HMRC issues the cumulative 1257L code, any overpaid tax comes back automatically through your next payslips; the emergency tax codes guide walks through the whole process.
How do I find out what code I should be on?
Your current code is on every payslip and on your P60, and the reasoning behind it is in your HMRC personal tax account, which lists the allowances and deductions that produced the number. If the account shows an estimate that is out of date, a company benefit you no longer have or a job you have left, you can change it there and a new code reaches your employer within a few weeks. Employers cannot change a code themselves: they apply whatever HMRC issues, so the fix always runs through HMRC rather than payroll.
Check your own code
Type any code, this page's and every other format HMRC issues:
Tax-free allowance of about £12,570.00 a year.
- L: you get the standard personal allowance.
Other codes people look up
2026/27 rules, checked 28 August 2026 by Hadi. If your code looks wrong, correct it via your personal tax account on gov.uk, refunds for the current year arrive through your pay automatically.