How to check your tax code and fix it if it is wrong
What 1257L, BR, K and emergency codes mean, why so many codes are wrong, and how to get a refund
Your tax code tells your employer or pension provider how much tax to take from each payslip. HMRC issues tens of millions of codes a year and a meaningful share of them are out of date or simply wrong. This guide shows you how to read yours in a minute, spot the common errors and get a refund if you have been overpaying.
What the numbers and letters mean
The number is your tax-free allowance with the last digit removed. 1257L means you get the full Personal Allowance of £12,570. If the number is lower, HMRC is collecting something, such as a company car, private medical cover or an old underpayment. If it is higher, you are getting extra allowances, perhaps for uniform costs or Marriage Allowance.
| Code | What it means |
|---|---|
| 1257L | Full Personal Allowance, the standard code |
| BR | All income taxed at 20%, usually for a second job or pension |
| D0 | All income taxed at 40% |
| D1 | All income taxed at 45% |
| 0T | No allowance, often used when a new employer has no details |
| K (e.g. K475) | Deductions exceed your allowance, so extra is added to your taxable pay |
| NT | No tax deducted |
| 1257L W1, M1 or X | Emergency code, calculated week by week or month by month with no regard to earlier pay |
An M suffix means you receive Marriage Allowance from your partner. An N suffix means you have given it away. Scottish codes start with S and Welsh codes with C.
Why codes go wrong
HMRC builds your code from what it knows about you. It often knows less than you think.
- You started a new job and your employer had no P45, so you were put on an emergency code or BR.
- You have two jobs or a job and a pension, and the allowance is attached to the wrong one or split badly.
- A benefit in kind, such as a car or medical insurance, ended but is still in your code.
- HMRC estimated untaxed income, such as savings interest or a side hustle, higher or lower than the real figure.
- An underpayment from a previous year is being collected and you did not know.
Emergency codes are the most common problem. They are fine for a month or two but if 1257L X is still on your payslip six months later, you have probably paid too much.
How to check and change it
The fastest route is the free HMRC app or your personal tax account at gov.uk. You can see the code for every employment and pension, the estimated income HMRC is using and every deduction built into the number.
- Compare the estimated income with your actual salary. Update it if it is out.
- Look at the deductions. Remove any benefit you no longer receive.
- Check that your allowance sits against your main income, not a small second job.
- If something is wrong and you cannot change it online, phone or write to HMRC. Have your National Insurance number and payslips ready.
Your employer cannot change your code. They apply what HMRC sends them, so complaining to payroll will not help.
How refunds arrive
If the error is in the current tax year, HMRC issues a new code to your employer and the overpayment comes back through your next pay as lower tax. Nothing else to do.
If you overpaid in an earlier year, HMRC will normally send a P800 calculation after the year ends. You can claim the money straight to your bank account through the app or your tax account. If you do nothing, HMRC posts a cheque, which takes longer. You can go back four tax years, so a claim made now can cover 2022/23 onwards.
Do not pay a claims company to do this. The process is free and takes minutes.
Watch out for
- Being on a K code without knowing why. Ask HMRC what the deduction is for.
- HMRC estimating a pay rise you did not get. This pushes you into paying more all year.
- Texts or emails promising a tax refund with a link. HMRC does not do this. Go to the app or gov.uk directly.
- Leaving an emergency code in place. It is your responsibility to check, not your employer's.