Tax code checker
Put in the code from your payslip and see what it actually means, plus what it is costing you against the standard code. 2026/27 rates.
More options
Your code only affects income tax. National Insurance is worked out separately from your earnings, so no code changes it.
Where to find your tax code
It is printed on every payslip, usually near your National Insurance number. Without a payslip to hand, it is in the HMRC app, in the Check your Income Tax service on gov.uk, and on any Tax Code Notice letter HMRC has sent you. Your P60 shows the code you finished last tax year on.
The app and the online service also show the codes for past years, and you can ask HMRC to email you whenever yours changes.
What every tax code letter means
| Code | What it means |
|---|---|
| 1257L | The standard code. £12,570 tax-free, the full Personal Allowance. |
| Other numbers with L | Same idea, different allowance. The number is your tax-free amount with the last digit dropped, so 1000L means £10,000. |
| M | You have received 10% of your partner's Personal Allowance through Marriage Allowance. |
| N | You have given 10% of your allowance to your partner. |
| T | Your allowance includes other calculations HMRC has made. It behaves like an L code; the letter just flags that something else is in the mix. |
| 0T | No allowance at all, but taxed through the normal bands. Usually a new job with no details, or an allowance used up elsewhere. |
| BR | Everything taxed at the basic rate, 20%, with no allowance. Meant for a second job or pension. |
| D0 | Everything at the higher rate, 40%. |
| D1 | Everything at the additional rate, 45%. |
| NT | No income tax on this income at all. Rare. |
| K before the number | Deductions worth more than your allowance, so an amount is ADDED to your taxable pay instead. Capped at half your pre-tax pay. |
| S prefix | Scottish rates apply. |
| C prefix | Welsh rates apply. They currently match England's. |
| W1, M1 or X on the end | Emergency, or non-cumulative: each pay period is taxed on its own rather than across the year. |
Is 1257L the right code for you?
It is if you have one job or pension, no company car or other taxable benefits, no untaxed income such as rent, no Marriage Allowance, no tax still owed from an earlier year, and income under £100,000. Change any one of those and a different code is the correct one, even though it takes more tax. The common cases:
- A second job or pension: usually BR on the smaller one, because your allowance is already used on the main one.
- Marriage Allowance: 1383M if your partner transfers £1,260 of their allowance to you, 1131N if you transfer it to them.
- A company car or private medical cover: a lower number, because the value of the benefit comes off your allowance.
- A State Pension alongside a workplace pension: a lower number on the workplace one, because the State Pension is paid with no tax taken off.
- Income over £100,000: a lower number, because the allowance shrinks by £1 for every £2 above it.
The one that catches people out
BR and 0T are not the same thing. Both take away your allowance, so they look interchangeable. They are not. A 0T code still runs your income through the normal bands, so part of it can reach 40%. A BR code taxes everything at 20% flat.
On a £60,000 salary that is £16,460 of income tax under 0T and £12,000 under BR. A £4,460 difference between two codes that both mean "no allowance". It is worth knowing which one you are actually on.
A K code cannot take everything
K codes worry people, because instead of tax-free pay they add an amount to your taxable income. If the deductions are large the tax can look enormous.
There is a statutory limit. Your employer cannot take more than half your pre-tax pay under a K code. The rest is not written off, it is carried forward, but it cannot all come out of one payslip. Most calculators ignore this and will happily show you a tax bill that could not legally be collected.
How to get a wrong tax code changed
HMRC sets your code and tells your employer which one to use, so your employer cannot fix it. The quickest route is to sign in to the HMRC app or the online service and correct the job, income or benefit details HMRC holds. If you cannot do it online, the Income Tax helpline is 0300 200 3300, 8am to 6pm on weekdays.
HMRC sends you and your employer the new code within 15 working days. Paid monthly, it should appear on your next or the following payslip. Paid weekly, by the third. If you have just started a new job, gov.uk asks you to wait 35 days first, which is how long your new income details take to reach HMRC.
Will you get the overpaid tax back?
Usually, and without having to ask. If HMRC has all your income details for the year, it tells your employer to refund the difference through your pay, normally from the first payslip on the new code. On an emergency code (W1, M1 or X) each pay period stands alone, so the money comes back once you are moved onto a normal code.
If the tax year has already ended, HMRC works it out for you and sends a P800 tax calculation letter, some time between June and March of the following year. Claimed online, the refund reaches your bank within 5 working days.
Questions
How do I check my tax code?
Look at your payslip, where it is printed near your National Insurance number, or sign in to the HMRC app or your gov.uk account. Then put it in the checker above with your salary to see what it means and what it costs against 1257L. If it looks wrong, HMRC is the one that changes it.
What does 1257L mean?
£12,570 of tax-free pay, which is the full Personal Allowance, and the code most people are on. What 1257L means in full covers the W1/M1 version and why the number has not moved since 2021.
Is BR the same as 0T?
No, and the difference costs money. Both remove your allowance, but 0T then taxes you through the normal bands while BR taxes everything at 20%. On a £60,000 salary that is £16,460 under 0T against £12,000 under BR, a difference of £4,460. Any checker that treats them as the same is wrong.
What is a K tax code?
It means untaxed income or benefits worth more than your allowance, so instead of tax-free pay you have an extra amount added to your taxable pay. Company cars, medical insurance and tax owed from an earlier year are the usual causes. There is a legal limit: your employer cannot take more than half your pre-tax pay under a K code, and anything above that is carried forward.
Why am I on an emergency tax code?
Codes ending W1, M1 or X are non-cumulative. Tax is worked out on each pay period on its own, as if you earned that amount every week or month, rather than across the year to date. It usually happens when you start a job and your employer does not have your previous income details. It normally corrects itself, and often produces a refund.
How do I know if my tax code is wrong?
Put it in the checker above with your salary and see what it costs against the standard code. A code that takes more is not automatically wrong: it is correct if you have a second job, a pension, or a taxable benefit like a company car. If none of those apply and your code is not 1257L, it is worth contacting HMRC. Overpaid PAYE is refundable.
Does my tax code change my National Insurance?
No. A tax code only affects income tax. National Insurance is worked out separately from your earnings, which is why an NT code still leaves NI coming off your pay.
Provenance
How this is worked out
Codes are parsed the same way payroll reads them, and the tax that follows uses the same engine as the take-home calculator, on 2026/27 rates from gov.uk, checked 26 September 2026. The letters and what they mean come from gov.uk tax codes. Where to find a code, how to change it and how refunds work come from gov.uk's updating your tax code and tax overpayments guides, read on 17 October 2026.
This tells you what a code does. It cannot tell you whether HMRC has the right code for you, because that depends on things only they and your employer can see. If the number looks wrong, HMRC is the place to fix it.