UK Tax Code Decoder
Enter your tax code from your payslip, P60, or P45 to understand what it means. Find out your Personal Allowance, which tax rate applies, and whether your code looks correct.
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Understanding UK tax codes
Your tax code tells your employer or pension provider how much income tax to deduct from your pay. It is set by HMRC based on your personal circumstances — including your income, benefits in kind, any outstanding tax debt, and whether you are eligible for the Marriage Allowance transfer.
Most codes consist of a number followed by a letter. The number indicates your tax-free allowance — multiply it by 10 to get the annual figure. So 1257L means £12,570 of tax-free income, which is the standard Personal Allowance for 2025–26. The letter indicates which rate schedule applies.
Common suffix letters
| Code | Meaning |
|---|---|
| L | Standard Personal Allowance — the most common code |
| M | Marriage Allowance received — you have received 10% of your partner's allowance |
| N | Marriage Allowance transferred — you have given 10% of your allowance to your partner |
| T | Other calculations needed — HMRC reviews your tax position more regularly |
| BR | Basic rate — all income taxed at 20%, no Personal Allowance (second jobs) |
| D0 | Higher rate — all income taxed at 40% (higher rate second job) |
| D1 | Additional rate — all income taxed at 45% |
| NT | No tax — no tax deducted from this source |
| 0T | No allowances — emergency or starter code with no personal allowance |
Prefix letters
A prefix before the number indicates a jurisdiction or special treatment. S means Scottish Income Tax rates apply. C means Welsh rates (currently identical to England and Northern Ireland). K is technically a prefix indicating the number is negative — your taxable income is increased rather than reduced.
W1, M1, and X suffixes
These are "non-cumulative" or "emergency" suffixes. Normally, your tax is calculated cumulatively across the year — if you overpay in April, it is corrected in May. W1 (weekly) and M1 (monthly) mean each pay period is calculated independently, which can result in overpayments that are only corrected at year end or via a P800. These are often applied when you start a new job and HMRC has not yet processed your P45 from your previous employer.
Frequently asked questions
What does 1257L mean?
1257L is the standard tax code for most UK employees in 2025–26. The number 1257 indicates a Personal Allowance of £12,570 (multiply by 10). The letter L means you are entitled to the standard tax-free Personal Allowance. This is the code used for most people with one job and no unusual adjustments to their tax position.
What does BR mean on a tax code?
BR means Basic Rate — all income from this source is taxed at the basic rate of 20% with no Personal Allowance applied. It is typically used for a second job or pension where your Personal Allowance has already been used up by your main income. If you have only one job and receive a BR code, contact HMRC as it may be incorrect.
What does a K tax code mean?
K codes are unusual in that they add income to your taxable pay rather than reducing it. They arise when you have untaxed income (such as a state pension, company benefit, or unpaid tax from previous years) that exceeds your Personal Allowance. A code of K500 means an additional £5,000 is treated as taxable income on top of your actual earnings. There is a limit to how much tax can be deducted — it cannot exceed 50% of your gross pay.
What is an emergency tax code?
Emergency tax codes are temporary codes applied when HMRC or your employer does not have enough information about your tax position. Common emergency codes are 1257L W1, 1257L M1, or 1257L X. The W1/M1 suffix means your tax is calculated on a week-by-week or month-by-month basis rather than cumulatively — which can result in overpaying tax during the year. Emergency codes are usually corrected automatically when HMRC receives the relevant information.
What does the S prefix mean on a Scottish tax code?
S at the start of a tax code (e.g. S1257L) means you pay Scottish Income Tax rates, which differ from the rest of the UK. Scotland has more tax bands: starter (19%), basic (20%), intermediate (21%), higher (42%), advanced (45%), and top (48%). The S code is assigned based on your main place of residence — if you live in Scotland but your employer has not applied an S code, contact HMRC.
Related calculators
This calculator provides estimates only. Results are based on the 2025–26 tax year. Credibrate is not a tax adviser. For personalised advice speak to a qualified accountant.