Tax Code Checker

Your tax code tells your employer how much tax-free income you are entitled to. The numbers represent your Personal Allowance divided by 10, and the letters indicate your situation. The standard code 1257L means £12,570 Personal Allowance with standard conditions.

The most common UK tax code is 1257L. This gives you the standard Personal Allowance of £12,570 for the 2025-26 and 2026-27 tax years (frozen until April 2028). The L suffix means you are entitled to the standard tax-free allowance with no special circumstances.

A K code means you have untaxed income (typically company benefits, state pension, or owed tax from a previous year) that exceeds your Personal Allowance. The K number × 10 is added to your taxable income each year. For example K475 adds £4,750 to your taxable income before bands are applied.

An emergency tax code (W1, M1, or X suffix) is a temporary code HMRC applies when they lack full information about your income — common after a job change without a P45. It taxes each pay period independently (non-cumulative). You usually overpay until HMRC issues the correct code; you can claim back via your Personal Tax Account.

HMRC sends a P2 PAYE coding notice when circumstances change — new company benefit, second job, starting state pension, switching from Marriage Allowance, or revised estimated income. If you think your new code is wrong, update details in your Personal Tax Account or call HMRC on 0300 200 3300.

An S prefix (e.g. S1257L) means you pay tax at Scottish rates, which have more bands than the rest of the UK. Your Personal Allowance still works the same way — the number × 10 — but the bands above it differ, so the same salary and allowance can produce a different tax bill. On a £35,000 salary, our decoder estimates £4,501 of tax under S1257L versus £4,486 under the equivalent rUK code 1257L. D2 is a separate special code: all your income from this job or pension is taxed at the Scottish intermediate rate of 21%. It works like BR/D0/D1 but only applies in Scotland.

W1 (week 1), M1 (month 1) and X mark an emergency tax code as non-cumulative — each pay period is taxed in isolation instead of averaging your Personal Allowance across the year. They typically appear when you start a new job or pension without giving your employer a P45, or when your circumstances change mid-year before HMRC issues an updated code. HMRC normally corrects the code automatically once it has full details, and any tax you overpaid on the emergency basis is refunded through your payroll (or via your Personal Tax Account) rather than needing a separate reclaim.

A K code appears when untaxed income — company benefits like a car or private medical insurance, State Pension (which is taxable but paid without tax deducted at source), or tax HMRC is collecting from a previous year — is worth more than your Personal Allowance. Since there's no allowance left to give you, HMRC instead adds the excess to your taxable pay. K475 specifically adds £4,750 (475 × 10) to your taxable income: on a £30,000 salary that means tax is calculated on £34,750 of taxable income, producing an estimated £6,950 of tax — about 23.17% of the £30,000 salary itself.