Tax Code Checker UK — What Does My Tax Code Mean?
Use this tax code checker to find out what your PAYE tax code means and whether it looks correct for the 2025/26 tax year. Your tax code tells your employer how much income tax to deduct from your pay, so getting it wrong can mean you overpay or underpay tax for months. Enter the code shown on your payslip or P45 and this tool will explain the letters and numbers in plain English, calculate your tax-free allowance and estimate your annual income tax. It covers all common UK tax codes including 1257L, BR, D0, K codes and emergency codes with W1 or M1 suffixes. If you have recently changed jobs or receive company benefits, checking your code is especially important.
Understanding What Your Tax Code Means
A UK tax code typically consists of a number followed by one or more letters. The number, multiplied by ten, gives your annual tax-free personal allowance. For example, 1257L means a £12,570 allowance with the standard L suffix. If your code contains a K prefix, it means your taxable benefits exceed your allowance, so extra tax is collected. Codes like BR and D0 apply a flat rate with no allowance, commonly used for second jobs. An emergency code with W1 or M1 means HMRC is calculating your tax on a non-cumulative basis, which often results in overpaying until the code is corrected.
How HMRC Sets Your Tax Code
HMRC calculates your tax code based on your personal allowance minus any adjustments for taxable benefits, untaxed income or underpaid tax from previous years. If you receive a company car, private medical insurance or other benefits in kind, your code number will be lower than 1257. You can view and update your tax code through your HMRC Personal Tax Account on GOV.UK. If you believe your code is wrong, contact HMRC on 0300 200 3300 or update your details online. Correcting an error early avoids a large over or underpayment at the end of the year.
What to Do If Your Tax Code Is Wrong
An incorrect tax code is one of the most common reasons people pay the wrong amount of tax. If your code shows a lower allowance than expected, check whether HMRC has included benefits you no longer receive or is collecting a debt from a previous year. You can use our take home pay calculator to see how a different code would affect your net pay. If you have been overtaxed, HMRC will usually issue a refund automatically once the code is corrected, or you can claim through self-assessment. For employed workers, reviewing your tax code alongside your National Insurance deductions gives the clearest picture of your overall payslip.
BR stands for Basic Rate and means all your income from that job is taxed at 20% with no personal allowance. This is commonly used for a second job.
An emergency tax code is temporary. Common codes include 1257L W1, 1257L M1 or 1257L X. The W1/M1 suffix means tax is calculated on a non-cumulative basis.
Compare against 1257L. If you have one job, no benefits and earn under £100,000, it should be 1257L. Check your HMRC Personal Tax Account online.
Only HMRC can change your tax code. Contact them on 0300 200 3300 or update details through your Personal Tax Account on GOV.UK.
A K tax code means your taxable benefits exceed your personal allowance. Your employer adds the K code amount to your taxable pay before calculating tax.
This tool provides guidance only. It interprets standard UK PAYE tax codes but cannot account for every individual circumstance. Always check your HMRC Personal Tax Account for the definitive tax code. This is not financial or legal advice.