Tax code checker
Your tax code, or PAYE code, tells your employer how much tax-free pay to give you before deducting income tax. Most people should be on 1257L for 2026/27, but codes go wrong after job changes, company benefits and HMRC estimates, and a wrong code means wrong tax every payday until it is fixed.
Calculator
Tax code checker
Tax-free allowance of about £12,570.00 a year.
- L: you get the standard personal allowance.
What tax code should I be on?
For a single job with no company benefits, no Marriage Allowance and income under £100,000, the answer is almost always 1257L: the standard personal allowance of £12,570.00, divided by ten, with an L. Scottish taxpayers see the same with an S in front (S1257L), Welsh taxpayers a C. A different code is not automatically wrong: company benefits like private medical insurance lower the number, Marriage Allowance changes the letter to M or N, and above £100,000 the allowance tapers away, so a code like 757L at £110,000 is the taper working correctly rather than an error. A second job normally gets BR, because your allowance is already used by the first. What should worry you is a code you cannot explain from your own circumstances, that is the one to query with HMRC.
What does 1257L mean?
Multiply the number by ten: £12,570 of pay each year on which no income tax is due, spread across your paydays. The L means the standard allowance with no special circumstances. Variants like 1257L M1, 1257L W1 or 1257L X add an emergency flag: each payday is taxed in isolation instead of cumulatively, usually temporary, after a job change.
The signs your code is wrong
A wrong tax code usually announces itself in one of four ways: no allowance where you should have one, an emergency flag that never clears, a K code with no explanation, or a number well below standard with nothing to justify it.
- BR or 0T on your only job: you are getting no tax-free allowance at all, and overpaying roughly £2,514.00 a year.
- An emergency suffix (W1/M1/X) that persists past two or three paydays.
- A K code you don't recognise: check what untaxed income HMRC thinks you have. A company car you have given back is a classic cause.
- A number far below 1257 with no benefits in kind to explain it.
The fix is the same in every case: check your tax code in your personal tax account on gov.uk and correct the estimated income and benefits HMRC holds. Refunds for the current year arrive automatically through your pay once the code changes.
Stuck on emergency tax?
A code ending W1, M1 or X is an emergency tax code: each payday is taxed in isolation instead of cumulatively, which usually means over-paying until HMRC sends your employer the right code. Try your emergency code and the standard code side by side in the checker above to see the monthly difference — the most common case, 1257L M1, has a dedicated emergency tax calculator page — and give your new employer your P45 (or the starter checklist) to speed the fix. Overpaid tax comes back automatically through your pay once the correct code lands; if you stopped work instead, the tax rebate calculator covers the free claim routes.
Common codes explained
What this checker does not do
It decodes the published HMRC format; it cannot know your personal circumstances, and it is not connected to HMRC. Only your personal tax account shows the code HMRC actually holds for you. No code you type here leaves your browser.
2026/27 rules, checked 28 August 2026 by Hadi. Sources and method on the about page.
How to use the tax code checker
- 1
Type the code exactly as it appears on your payslip, including any letters after the number.
- 2
Enter your salary so the checker can price what that code costs against the standard one.
- 3
Read the decode: what the code means, what allowance it gives you, and whether it looks like an emergency code.
- 4
If it is wrong, follow the steps for telling HMRC, and check whether a refund is owed for earlier months.
When should you use the tax code checker?
Use it when your code is anything other than the standard one, or when your take-home changed without your pay changing.
You started a new job
Without a P45 your employer may put you on an emergency code, which taxes you as if the allowance had already been used.
Your take-home dropped with no pay change
A code change is the usual cause, and it repeats every month until somebody corrects it.
Your code has a K in front
A K code adds to your taxable pay instead of sheltering it, usually because of a benefit or an underpayment being collected.
You have more than one job
BR or D0 on a second job is normal. BR on your only job is not, and costs the full basic-rate tax on the allowance.
Where to go next
- Payslip checkerTo check every other line on the payslip while you are there.Open
- Tax rebate calculatorTo work out what a wrong code has already cost you.Open
- Income tax calculatorTo see the tax the correct code should produce.Open
All 51 calculators share one tested engine, so a figure from the tax code checker agrees with every other page here. See the full calculator index or the pay and tax guides.