Tax code checker
Type the tax code from your payslip, P45 or HMRC app. You'll see what each part means, your tax-free pay for 2026/27 and whether it looks wrong.
Your result appears here as you type.
An estimate from the figures you entered. It is not financial advice.
How to read a tax code
Most codes are a number followed by a letter. Multiply the number by 10 and you have the pay you can earn tax-free in that job over the year: 1257 gives £12,570. The letter tells your employer how to treat it, and a letter in front tells them which country's rates to use.
| Part | Meaning |
|---|---|
| L | The standard tax-free personal allowance |
| M | You've received 10% of your partner's allowance (Marriage Allowance) |
| N | You've given 10% of your allowance to your partner |
| T | HMRC needs to review other items in your code |
| K (in front of the number) | Untaxed income bigger than your allowance; the amount is added to your pay |
| S or C (in front) | You pay Scottish (S) or Welsh (C) income tax |
| BR, D0, D1 | All pay taxed at one rate: basic, higher or additional in England, Wales and NI |
| SD0 to SD3 | All pay taxed at Scotland's intermediate, higher, advanced or top rate |
| 0T | No tax-free allowance from this job |
| NT | No tax taken from this income |
| W1, M1 or X (at the end) | Emergency basis: the allowance isn't carried forward week to week |
Signs your tax code is wrong
- You have one job but the code is BR, 0T or D0.
- The code still ends in W1 or M1 several months after you started a job.
- Your code starts with S but you live in England, or the other way round.
- You stopped getting a company car or medical cover and the code hasn't gone up.
- You have two jobs and both have 1257L, so you're getting the allowance twice. You'll owe tax later.
If one of these fits, check the code in your HMRC personal tax account or the HMRC app. Any tax overpaid in the year normally comes back through your pay once the code is fixed, or HMRC sends a refund after the year ends.
How this checker works
It reads the code the same way payroll software does and works out the tax for a full year on that code using 2026/27 rates. For the comparison it uses the code you'd expect: 1257L (or S1257L or C1257L) for one job, and BR for a second job when your main job uses your allowance. It assumes you've had this pay all year. An emergency code taken for only part of the year usually sorts itself out by the year end.
Questions people ask
What does 1257L mean?
1257L is the standard tax code for 2026/27. The number means you get £12,570 of tax-free pay over the year, and L means you get the normal personal allowance. Most people with one job or pension have it.
Why am I on an emergency tax code?
Codes ending in W1, M1 or X usually appear when you start a new job without a P45, or when HMRC hasn’t yet got your details. Your allowance is applied one week or month at a time instead of across the year so far, which can mean too much tax. Give your employer your P45 or fill in their starter checklist, and it should correct itself.
What is a BR tax code?
BR means all the pay from that job is taxed at the 20% basic rate, with no tax-free amount. It’s normal on a second job or pension when your allowance is used by your main job. On your only job it is usually a mistake and you are probably overpaying.
What does a K tax code mean?
A K code means you have income HMRC hasn’t taxed elsewhere, such as a company car or unpaid tax from an earlier year, that’s bigger than your allowance. The number times ten is added to your taxable pay. Your employer can’t take more than half your pay in tax because of a K code.
How do I change my tax code?
Tell HMRC through your personal tax account, the HMRC app or by phone. HMRC sends the new code to your employer. You can’t change it by asking your employer, because they have to use the code HMRC gives them.
What does 0T mean?
0T means you get no tax-free allowance from this job. It’s used when your allowance has gone (on incomes over £125,140) or your employer doesn’t have enough information. If neither applies, contact HMRC.
Sources
- What your tax code means (GOV.UK)
- Emergency tax codes (GOV.UK)
- Income Tax rates and Personal Allowances (GOV.UK)
- Scottish Income Tax rates and bands 2026 to 2027 (Scottish Government)
Rates and review
Uses rates for the 2026/27 tax year. Figures last checked against the sources on 25 October 2026.
Written by author to be named. Reviewed by qualified reviewer to be named.
See how we calculate and the disclaimer. Spotted a wrong figure? Report a problem.