Updated for the 2026/27 tax year
The C1257L tax code
You’re entitled to the standard tax-free Personal Allowance
What it does to your pay
C1257L gives you £12,570 of pay before income tax starts, spread across the year. That figure is the number in the code multiplied by 10 — the code number is the tax-free amount with its last digit replaced by the letter.
The letter does not change that arithmetic. It records WHY your allowance is the size it is, which matters when you are checking whether the code fits your circumstances rather than when you are working out the tax.
Source: Reg 7(1)(a): a code is "a combination of letters, numbers or both for use in accordance with the tax tables to establish free pay". The allowance itself is ITA 2007 s.35(1).
A worked example
On pay of £30,000 for the year, C1257L makes £17,430 taxable and produces £3,486 of income tax. That is the same as the standard code would produce on the same pay.
- £17,430 at 20% = £3,486
Income tax only — National Insurance, student loan repayments and pension contributions are separate and are not included here.
How C1257L is written on a payslip
C1257L is the code. Anything printed after it is a marker, and the markers this site recognises are W1, M1, X and NONCUM — HMRC’s payroll names for the non-cumulative basis, which the regulations set out at regs 26–31 and which the emergency-code page explains in full. Whether a marker changes anything for THIS code is a question for the regulation quoted above, not for the marker.
The space is optional and payslips print it both ways. C1257L W1 and C1257LW1 are the same string as far as this site is concerned: the checker upper-cases what you type and strips the spaces out before it looks the code up, so either spelling reaches this page.
Is it right for you?
Check the number against what you expect your allowance to be. If it is lower, something has been deducted from it — a benefit in kind, untaxed income, or tax owed from a previous year — and your coding notice will say which.
Whatever the answer, the code HMRC holds for you is the one that governs, and it is on your Personal Tax Account. If your tax code is wrong sets out how to get it changed.
Common questions
What does the C1257L tax code mean?
You’re entitled to the standard tax-free Personal Allowance. It gives you £12,570 of pay before income tax starts, spread across the year.
How much tax does C1257L take on £30,000 a year?
On pay of £30,000 for the year, C1257L makes £17,430 taxable and produces £3,486 of income tax. That is what the standard code produces on the same pay. Income tax only — National Insurance, student loan repayments and pension contributions are separate and are not included.
Is C1257LW1 the same code as C1257L?
Yes. W1, M1, X and NONCUM are the markers HMRC uses for the non-cumulative basis, and a marker after C1257L leaves the code itself unchanged. The space is optional: this site's checker reads C1257LW1 and C1257L W1 identically, because it strips spaces before looking the code up.
Independent tool not affiliated with HMRC. For your official code, log in to your Personal Tax Account. Check your tax code on GOV.UK.
Letters and law are not the same thing. The PAYE Regulations create these codes by describing what they DO — “the basic rate code”, “the nil tax code” — and, with one exception, never write down the letters HMRC prints on your payslip. The letters are HMRC’s naming for those functions. This site labels which is which on every page, and the sources page shows the search behind that statement.
The figures and rules on this site are taken from the Income Tax (Pay As You Earn) Regulations 2003, the Income Tax Act 2007 and HMRC’s published guidance, and are shown as they were found. They have not been signed off by a reviewer. Where the law and HMRC’s naming differ, the page says which is which rather than blending them. For anything that affects a decision, the cited document governs and this site does not.