Tax code checker

How to use our tax code checker

Is my tax code correct? Use our free online tax code checker to find out. Enter your annual salary and your current tax code. The results show what each letter means and whether your code looks right based on your salary alone.

Not sure where to find your tax code? Check:

• your payslip
• your PAYE coding notice (HMRC also call this a Tax Code Notice)
• your P45, which shows the code you had when you left a job
• your Check your Income Tax online account or the HMRC app

Make sure the code is for the tax year you’ve entered.

This UK tax code checker works for tax codes in England, Wales and Northern Ireland. Scottish codes start with an S and use different rates. If yours does, read Income Tax in Scotland on GOV.UK.

Your tax code changes when your circumstances change, so always use your most recent code for accurate results. A code from an old P45, such as one from 2018, won’t match your situation today.

Based on your code, the checker shows the Income Tax rate you’re taxed at, any allowances you claim, and whether you’re repaying tax owed to HMRC, which a K code shows. The Results section gives a brief breakdown of each letter. The Calculation details section underneath explains each letter in more depth.

There are many letter and number combinations, so please treat these results as an estimate. If something doesn’t add up, contact HMRC or check your details in Check your Income Tax on GOV.UK. 

What your tax code means

How to read your tax code

Your tax code is a number and a letter. Your employer or pension provider uses it to work out how much tax to take from your pay.

The number is your tax-free amount, in tens. Multiply it by 10 to get the amount in pounds. For 2026/27, the standard Personal Allowance (the amount you can earn before paying Income Tax) is £12,570, so 1257L means £12,570.

The letter shows your tax situation. The table below explains each one.

Common tax code letters and what they mean

Emergency codes end in W1, M1, X or NONCUM, for example 1257L W1. They’re usually temporary and used after a job change. You’re taxed only on what you’re paid in that week or month. 

Scottish and Welsh tax codes

If you live in Scotland or Wales, your tax code starts with a letter that shows which rates apply.

• S means Scottish Income Tax rates apply. See the Scottish rates on GOV.UK.
• C means Welsh Income Tax rates apply. See the Welsh rates on GOV.UK.

When your tax code might be wrong

Your tax code may be wrong if any of the situations below apply to you. HMRC can often correct it once your details are up to date. 

Signs your tax code may be incorrect

• You’ve started a new job, and you’re still on an emergency code more than 35 days later. An example is 1257L W1 or 1257L M1.
• You have more than one job or pension, and your codes don’t share one Personal Allowance between them.
• You earn over £100,000, and your code doesn’t show a lower number for the tapered Personal Allowance. For example, on a salary of £110,000 with no other income or deductions, your Personal Allowance falls by £5,000 to £7,570 (2026/27), so your code would be 757L. 
• You receive income that isn’t taxed through your pay, such as dividends or savings interest above your allowances, and your code hasn’t been adjusted.
• You’ve claimed Marriage Allowance, but your code doesn’t show an M or an N.
• You’ve received a P800 tax calculation showing you’ve paid too much or too little tax.

What to do if your tax code is wrong

1. Check your details first. Sign in to Check your Income Tax, which is part of your Personal Tax Account on GOV.UK. You can also call HMRC on 0300 200 3300, Monday to Friday, 8am to 6pm.
2. If you’ve underpaid, HMRC may adjust your code to collect the tax over one or more years. This can show as a K code. They may also write to you about the amount owed.
3. If you have untaxed income, you may need to file a Self Assessment tax return. Self Assessment is the system HMRC uses to collect Income Tax on income that isn’t taxed through your pay. This is especially likely if you have savings interest or dividends alongside your salary.

I think my tax code is wrong

If you think your tax code is wrong, it’s worth checking. Usually the problem is missing or out-of-date information, which HMRC can update.

Before you contact HMRC, have ready your jobs and pensions (with start and end dates), your estimated taxable income, any company benefits, state benefits or State Pension, and any expenses you’ve claimed tax relief on.

If you’ve just started a job, wait 35 days before contacting HMRC. Once your details are updated, HMRC will tell you and your employer your new code within 15 working days.

If you’ve overpaid, HMRC usually refund it through your pay. If you’ve underpaid, they may collect it over one or more years. After the tax year, HMRC may send you a P800 tax calculation, which shows whether you’ve paid the right amount. 

Choose your next step:

• Slightly wrong code: contact HMRC through Check your Income Tax or on 0300 200 3300.
• Untaxed or complex income: you may need to file a Self Assessment tax return.
• Unsure: book a 30-minute consultation with a UK-qualified accountant through Taxfix.

My tax code isn’t recognised

The Taxfix tax code checker may not recognise some codes, such as a very new code, a bespoke code, or a Scottish code. That doesn’t mean your code is wrong.

Contact HMRC to confirm why you’re on the code you have. In the meantime, the table above explains the most common tax code letters.

To learn more, see our glossary entry on tax codes.

FAQ: Tax code checker

How do I check my tax code?

You can check your tax code online by signing in to Check your Income Tax on GOV.UK. You can also find it in the HMRC app, on your payslip, or on a Tax Code Notice letter. 

What does the letter L mean in my tax code?

L means you get the standard Personal Allowance, which is £12,570 for 2026/27. Most people with one job or pension have a code such as 1257L. 

What is an emergency tax code?

An emergency tax code ends in W1, M1, X or NONCUM, such as 1257L W1. It means you’re taxed only on what you’re paid in that week or month, and it’s usually temporary after a job change. 

Why has my tax code changed?

Your tax code changes when your circumstances change. Common reasons include starting a new job, taking on a second job or pension, receiving taxable state benefits, or claiming Marriage Allowance. 

What does a K tax code mean?

A K code means you have income or deductions above your Personal Allowance that aren’t already taxed, such as tax owed from a previous year. With a K code, your employer can’t take more than half of your pre-tax pay. 

Can I have more than one tax code?

Yes. You get a separate tax code for each job or pension. Your main job usually has the standard code, while other jobs or pensions usually have BR, D0 or D1. 

What should I do if my tax code is wrong?

Check your details in Check your Income Tax on GOV.UK first. If you can’t use the online service, call HMRC on 0300 200 3300. HMRC will tell you and your employer about a corrected code within 15 working days. 

Do I need to file a tax return if my tax code is wrong?

You don’t always need to file a tax return. Many tax code problems are fixed by updating your details with HMRC, but you may need a Self Assessment return if you have untaxed income, such as savings interest or dividends above your allowances.

This article provides general information only and is not personalised tax advice.