27 April 2026
UK tax codes explained: what yours means and how to fix it
A complete guide to UK tax codes: what 1257L, BR, K, and emergency codes mean, how to check yours is correct, and what to do if it's wrong.
Your tax code is the short string of numbers and letters your employer or pension provider uses to work out how much Income Tax to take off your pay. Get it wrong and you could pay too much, or too little, without ever realising until HMRC catches up with you.
You'll find it on your payslip, your P45 or P60, or in your HMRC personal tax account. Here's what it actually means, and what to do if it looks wrong.
The standard tax code for 2026/27
For most people with one job and no complications, the code is 1257L. The number is your tax-free Personal Allowance divided by 10 (£12,570 becomes 1257), and the L means you're entitled to the standard allowance.
If your circumstances are simple, that's the code you should see. Anything else usually means HMRC is accounting for something specific: a second income, a benefit in kind, unpaid tax from a previous year, or a devolved tax rate.
What the letters in your tax code mean
The letter after the numbers tells you which rule is being applied:
- L: you're entitled to the standard tax-free Personal Allowance
- M: you've received a transfer of 10% of your partner's Personal Allowance (Marriage Allowance)
- N: you've transferred 10% of your Personal Allowance to your partner (Marriage Allowance)
- K: you have income HMRC isn't otherwise taxing that's larger than your Personal Allowance, so tax is added rather than an allowance deducted
- S: your income is taxed using the Scottish rates and bands
- C: your income is taxed using the Welsh rates and bands
- T: your code includes other calculations to work out your Personal Allowance
- BR: all your income from this job or pension is taxed at the basic rate, usually because you have more than one job or pension
- D0: all your income from this job or pension is taxed at the higher rate
- D1: all your income from this job or pension is taxed at the additional rate
- 0T: your Personal Allowance has been used up, or your employer doesn't yet have enough information to give you a proper code
- NT: you're not paying any tax on this income
Second-job codes if you're a Scottish or Welsh taxpayer
BR, D0, and D1 are the rest-of-UK flat-rate codes for a second job or pension. Scottish and Welsh taxpayers see their own versions instead, reflecting their own bands:
- Scotland: SBR (basic rate, 20%), SD0 (intermediate rate, 21%), SD1 (higher rate, 42%), SD2 (advanced rate, 45%), SD3 (top rate, 48%)
- Wales: CBR (basic rate), CD0 (higher rate), CD1 (additional rate), currently the same 20%/40%/45% rates as the rest of the UK, since Welsh rates haven't diverged so far
Emergency tax codes
An emergency tax code is applied when HMRC doesn't yet have full details of your income, usually when you start a new job without a P45, begin getting a pension, or start receiving company benefits. It works on a non-cumulative basis, meaning each pay period is taxed in isolation rather than against your total income for the year, which can mean you overpay tax temporarily.
You'll recognise an emergency code by its suffix: W1 for weekly pay, M1 for monthly pay, or X where your pay dates vary (for example, 1257L W1 or 1257L M1). It's usually temporary. Handing your new employer a P45 or completing a starter checklist promptly is the fastest way to avoid one building up, and any tax overpaid on an emergency code is refundable once HMRC has the full picture.
How to check your tax code is right
Compare your code against your circumstances. If you have a single job and nothing unusual going on, you should be on 1257L (or the Scottish or Welsh equivalent). If you have a second job, that one will typically show BR, D0, D1, or their Scottish/Welsh equivalents. If you've claimed Marriage Allowance, expect an M or N.
The most reliable way to check is your personal tax account at gov.uk/personal-tax-account, which shows your current code, the reasoning behind it, and lets you flag if something looks wrong.
What to do if your tax code is wrong
Contact HMRC through your personal tax account (changes usually reach your employer within around two weeks) or by phone if it's urgent. Once your code is corrected, your employer applies it automatically, and any tax you've overpaid is refunded either through your pay or as a separate P800 calculation.
Our Income Tax Calculator and Salary Calculator apply the standard Personal Allowance and bands, which is a useful comparison if you're on 1257L or its Scottish/Welsh equivalent. They don't currently take a tax code as an input, though, so if yours reflects something else, like a K code, a second-job code, or a Marriage Allowance adjustment, your actual PAYE deduction will differ from what the calculators show.