Tax Code Checker
Decode your HMRC tax code and understand exactly what it means for your tax. Enter your tax code to see a plain-English explanation and your estimated income tax.
New to tax codes? See our UK Tax Codes Explained guide for what the letters and numbers mean.
Key Takeaway
Your tax code tells your employer how much tax to deduct. The most common code is 1257L, which gives you a £12,570 tax-free Personal Allowance.
Key Facts
Standard Code
1257L
S Prefix
Scottish rates
K Prefix
Extra tax owed
W1/M1
Emergency code
UK Tax Code Letters & Prefixes
Every letter and prefix you might see on an HMRC tax code, with what it means.
| Letter | Type | Meaning |
|---|---|---|
| L | Suffix | Standard tax-free Personal Allowance |
| M | Suffix | Marriage Allowance recipient (10% of partner’s allowance transferred to you) |
| N | Suffix | Marriage Allowance transferor (you transferred 10% of your allowance) |
| T | Suffix | HMRC needs to review your tax code |
| S | Prefix | Scottish Income Tax rates apply |
| C | Prefix | Welsh Income Tax rates apply |
| K | Prefix | Income not taxed another way exceeds your allowances |
| BR | Special | All income taxed at basic rate (20%) |
| D0 | Special | All income taxed at higher rate (40%) |
| D1 | Special | All income taxed at additional rate (45%) |
| NT | Special | No tax deducted |
| 0T | Special | No Personal Allowance — all income taxed through bands |
| W1 / M1 / X | Modifier | Emergency / non-cumulative basis — each pay period taxed independently |
Look Up a Specific Tax Code
Click any code for a full explanation — what it means, your Personal Allowance, estimated take-home pay, and when to use it.
How UK Tax Codes Work
Your HMRC tax code is used by your employer or pension provider to calculate how much income tax to deduct from your pay. The code is made up of numbers and letters that together determine your tax-free amount and the rates applied.
The numbers in your tax code represent your tax-free Personal Allowance. Multiply the number by 10 to get your allowance. For example, the number 1257 means a Personal Allowance of £12,570. This is the amount you can earn before paying income tax.
The letters tell your employer about your situation and which tax rates to use. The most common suffix is L, which means you are entitled to the standard Personal Allowance. Prefixes like S (Scottish) or C (Welsh) indicate which country’s tax rates apply.
K codes work differently. Instead of giving you a tax-free amount, the number is added to your taxable income. This happens when you have untaxed income (such as company benefits) that exceeds your Personal Allowance. For example, K475 means £4,750 is added to your taxable income.
An emergency tax code (indicated by W1, M1, or X after your code) means HMRC does not have enough information to give you a correct code. Each pay period is taxed independently rather than cumulatively, which often results in overpayment. Contact HMRC to resolve this.
Not sure which code applies? Decode yours here
Enter your HMRC tax code below for a plain-English breakdown plus an estimated take-home pay.
You are entitled to the standard tax-free Personal Allowance. This is the most common tax code suffix.
Your tax-free Personal Allowance is £12,570.
Personal Allowance
£12,570
| Code | Description |
|---|---|
| The most common tax code for 2024-25 onwards, reflecting a Personal Allowance of £12,570. | |
| Scottish version of the standard code — same allowance, different tax rates. | |
| Welsh version of the standard code. | |
| Basic rate — typically used for a second job. | |
| K code — £4,750 is added to your taxable income (e.g., company car benefit). | |
| Emergency tax code — temporary, non-cumulative basis. |
Next: turn your tax code into £ figures
Now you know what your code means, run the numbers for your situation.
See your take-home pay
Net pay after income tax, NI, student loan and pension — using any tax code.
Calculate your income tax
Band-by-band breakdown for England, Wales, Scotland and Northern Ireland.
Check National Insurance
Class 1 for employees, Class 2 & 4 for self-employed — see your effective rate.
Frequently asked questions
What does my tax code mean?
Your tax code tells your employer how much tax-free income you are entitled to. The numbers represent your Personal Allowance divided by 10, and the letters indicate your situation. The standard code 1257L means £12,570 Personal Allowance with standard conditions.
What is the most common UK tax code?
The most common UK tax code is 1257L. This gives you the standard Personal Allowance of £12,570 for the 2025-26 and 2026-27 tax years (frozen until April 2028). The L suffix means you are entitled to the standard tax-free allowance with no special circumstances.
What does a K tax code mean?
A K code means you have untaxed income (typically company benefits, state pension, or owed tax from a previous year) that exceeds your Personal Allowance. The K number × 10 is added to your taxable income each year. For example K475 adds £4,750 to your taxable income before bands are applied.
What is an emergency tax code?
An emergency tax code (W1, M1, or X suffix) is a temporary code HMRC applies when they lack full information about your income — common after a job change without a P45. It taxes each pay period independently (non-cumulative). You usually overpay until HMRC issues the correct code; you can claim back via your Personal Tax Account.
Why has my tax code changed?
HMRC sends a P2 PAYE coding notice when circumstances change — new company benefit, second job, starting state pension, switching from Marriage Allowance, or revised estimated income. If you think your new code is wrong, update details in your Personal Tax Account or call HMRC on 0300 200 3300.
Sources
Related Calculators
Last updated April 2026. Reflects 2026-27, 2025-26 and 2024-25 tax year rates.
Related Calculators
Learn More
UK Tax Codes Explained 2026-27: What Your HMRC Code Means
HMRC tax codes for 2026-27 in plain English: decode 1257L, BR, D0, D1, NT, 0T, K codes, W1/M1 emergency, S-prefix Scottish and C-prefix Welsh. How to check your code and fix it if wrong.
Understanding UK Income Tax Bands
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HMRC Interest Rates on Late Tax Payments 2025-26
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