Tax Code Checker 2026/27
Enter your UK tax code below to find out what it means, how much tax-free income you get, and how it compares to the standard tax code. This tool works entirely in your browser -- no data is sent anywhere.
How to use
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About This Tool
The Tax Code Checker helps you understand what your UK tax code means. It decodes the numbers and letters in your tax code, shows how much tax-free income you receive, and estimates how your tax compares to the standard personal allowance.
All calculations run entirely in your browser. No data is sent to any server, so your information stays private.
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How to Use the Tax Code Checker
Find Your Tax Code
Your tax code can be found on your payslip, P45, P60, or in a letter from HMRC. You can also find it on your Personal Tax Account on GOV.UK.
Enter Your Tax Code
Type your tax code into the input field above. You can include prefixes (S for Scottish, C for Welsh) and suffixes (W1, M1, X for emergency codes). The tool is not case-sensitive.
Review Your Results
Click "Check Tax Code" to see a full breakdown including:
- What your code means in plain English
- Your tax-free allowance amount
- Comparison to the standard 1257L code
- Estimated tax at different salary levels
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Common Tax Code Letters Explained
| Code / Letter | Meaning |
|---|---|
| L | You are entitled to the standard tax-free personal allowance. |
| M | You have received 10% of your partner's personal allowance through Marriage Allowance. |
| N | You have transferred 10% of your personal allowance to your partner through Marriage Allowance. |
| T | Your tax code includes other calculations to work out your personal allowance (e.g. income over £100,000). |
| 0T | Your personal allowance has been used up, or your employer does not have the information needed to give you a tax code. |
| BR | All income from this job or pension is taxed at the basic rate (20%). |
| D0 | All income from this job or pension is taxed at the higher rate (40%). |
| D1 | All income from this job or pension is taxed at the additional rate (45%). |
| NT | No tax is deducted from this income. |
| K | You owe tax from a previous year or on benefits; an amount is added to your taxable income instead of receiving an allowance. |
| S (prefix) | Scottish Income Tax rates apply to your earnings. |
| C (prefix) | Welsh Income Tax rates apply to your earnings. |
| W1 / M1 / X | Emergency tax code (non-cumulative). Each pay period is treated independently rather than cumulatively. |
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The Standard Tax Code: 1257L
The most common tax code in the UK is 1257L. This is the standard code for the 2026/27 tax year. It means you have a personal allowance of £12,570, which is the amount you can earn before you start paying income tax.
The number 1257 is your personal allowance divided by 10 (£12,570 / 10 = 1257). The letter L confirms you are entitled to the standard personal allowance.
If your tax code is different from 1257L, it usually means HMRC has adjusted your allowance. This could be because you receive company benefits, owe tax from a previous year, or have multiple sources of income.
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Emergency Tax Codes
Emergency tax codes are temporary codes used when HMRC does not have enough information to issue your correct tax code. They are identified by the suffixes W1, M1, or X after your normal tax code.
Common reasons for being placed on an emergency tax code include:
- Starting a new job without providing a P45
- Starting a new job after being self-employed
- Receiving company benefits or the State Pension for the first time
On an emergency tax code, each pay period is treated independently. This means you do not benefit from any unused personal allowance from earlier months, which often results in overpaying tax.
HMRC usually updates your tax code automatically once they receive your details. If your code is not updated within a few months, contact HMRC.
M
Marriage Allowance Codes (M and N)
Marriage Allowance lets you transfer £1,260 (10% of the standard personal allowance) to your husband, wife, or civil partner. This can reduce their tax by up to £252 per year.
Code ending in M (e.g. 1382M)
You have received 10% of your partner's personal allowance. Your tax-free allowance increases from £12,570 to £13,830.
Code ending in N (e.g. 1131N)
You have transferred 10% of your personal allowance to your partner. Your tax-free allowance decreases from £12,570 to £11,310.
To be eligible, one partner must earn less than the personal allowance (£12,570) and the other must be a basic rate taxpayer (earning between £12,571 and £50,270).
K
K Codes Explained
A K code means you have income that is not being taxed another way and it is worth more than your tax-free allowance. Instead of receiving an allowance, the number in your K code is multiplied by 10 and added to your taxable income.
For example, a tax code of K497 means £4,970 is added to your taxable income. Common reasons for a K code include:
- Tax you owe from a previous year that is being collected through your wages
- Company benefits (such as a company car or medical insurance) that exceed your personal allowance
- State Pension income that uses up your entire allowance
There is a safeguard with K codes: your employer cannot take more than 50% of your gross pay in tax in any pay period, even if the K code would normally result in a higher deduction.
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What To Do If Your Tax Code Is Wrong
If you believe your tax code is incorrect, you should take action to avoid overpaying or underpaying tax. Here is what to do:
- Check your tax code online using your Personal Tax Account on GOV.UK or the HMRC app
- Review your coding notice (form P2) which HMRC sends when your code changes - it explains how your code was calculated
- Contact HMRC by phone on 0300 200 3300 if you cannot resolve it online
- Do not contact your employer directly about your tax code - only HMRC can change it
If you have overpaid tax because of a wrong code, HMRC will usually send you a refund (a P800 calculation) or adjust your code for the rest of the year so you pay less tax going forward.
If you have underpaid tax, HMRC may collect the underpayment by adjusting your tax code for the following year, spreading the amount owed over 12 months.
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Disclaimer
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