UK PAYROLL
UK tax codes, decoded.
A tax code is HMRC's instruction to your employer about how much tax to deduct. Find out what your code means, when it changes, and what to verify.
Educational estimates only. Not tax, legal, financial, payroll or employment advice. Verify with your employer's payroll team or HMRC.
Common UK tax codes
Common questions
What does 1257L mean?
The number 1257 multiplied by 10 (£12,570) is your tax-free Personal Allowance for 2026/27. The L means you get the standard allowance with no adjustments. Most full-time employees on a single job have this code.
Why does my tax code keep changing?
HMRC reissues codes when your circumstances change: a second job, taxable benefits like a company car, owed tax from a previous year, or a personal allowance adjustment. Each change comes with a P9 coding notice from HMRC.
What is the difference between cumulative and non-cumulative codes?
A cumulative code (e.g. 1257L) reconciles your tax against the year so far each pay period. A non-cumulative code (1257L W1, M1 or X) treats each period independently, ignoring earlier earnings. Non-cumulative is used as an emergency mode and tends to over-tax until corrected.
How do I correct a wrong tax code?
Log in to your Personal Tax Account at gov.uk, check your current code and any underlying adjustments. If wrong, update the income or benefit in question. HMRC will issue a corrected P9 to your employer, usually within one or two pay cycles.
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Open the toolPayslipIQ provides educational information and estimated calculations only. It does not provide tax, legal, financial, payroll, accounting, pension, benefits or employment advice. Always verify your payslip, tax code, deductions and take-home pay with your employer's payroll department, HMRC, your pension provider, a qualified accountant, tax adviser or another appropriately qualified professional.