How to Check Your Tax Code, and What to Do If It's Wrong

Where to find your tax code

Your tax code appears on your payslip, on a P60 at year end, and in your HMRC online account or the HMRC app. If you are employed, your employer receives the code from HMRC and applies it automatically. You do not need to manually enter it anywhere on the payroll side.

The most common code for employees with a single job and no unusual circumstances is 1257L. This means you get the standard personal allowance of £12,570 for 2026/27, with no deductions or additions from other income.

Codes with letters like W1 or M1 at the end indicate emergency or non-cumulative tax treatment. These can cause overpayment early in the year and should be corrected by contacting HMRC.

• 1257L: Standard code for most employed taxpayers.
• K codes: Negative allowance, you have untaxed income above your personal allowance.
• BR: Basic rate on all income, usually for a second job.
• NT: No tax, rarely used, specific circumstances only.
• D0 / D1: Higher or additional rate on all income.

Common reasons for an incorrect code

The most frequent causes of a wrong tax code are untaxed benefits in kind (like a company car), HMRC assuming you have income you no longer receive, or a late notification after changing jobs. If HMRC has the wrong information, your payslip deductions can be higher or lower than they should be.

Using an emergency code (often BR or Week 1/Month 1) at the start of a new job is normal, but it should be replaced within a few months once your employer has submitted the starter checklist. If you stay on an emergency code for more than two months, contact HMRC.

People with multiple jobs or pension income alongside employment sometimes receive codes that do not correctly reflect their combined tax position. Use the PAYE income tax estimator on GOV.UK to verify whether the code looks right for your total income.

• New job and employer has not submitted starter declaration.
• Company car or taxable benefit added to your code.
• Income from a previous job or pension creating unexpected deductions.
• Underpayment from a prior year being collected through the code.

How to correct a wrong tax code

Contact HMRC directly through your Personal Tax Account at gov.uk, by phone on 0300 200 3300, or by post. You will need your National Insurance number and employer details. HMRC can issue a revised P6 to your employer, which should update your payslip within one or two pay periods.

If you have overpaid tax because of an incorrect code, HMRC typically issues a refund automatically after the tax year ends. You can also request an earlier repayment if the overpayment is significant.

Keeping your HMRC account details updated, particularly when starting a new job, stopping work, or changing benefits, reduces the chance of code errors persisting across multiple pay periods.

• Use Personal Tax Account at gov.uk to view and query your code.
• Phone HMRC: 0300 200 3300 (have NI number ready).
• Allow 1–2 pay periods for a corrected code to take effect.
• Overpayments are usually refunded automatically at year end.