Tax code checker: what does my tax code mean?

What the letters in a tax code mean

Source: GOV.UK: What your tax code means and Understanding your employees' tax codes, checked 23 October 2026.

What the numbers mean

The number tells your employer or pension provider how much tax-free income you get from them in the tax year. You usually multiply it by 10: 1257L means £12,570, the standard Personal Allowance for 2026 to 2027, and S1257L is the same allowance with Scottish rates. To get your number, HMRC starts with your Personal Allowance and takes off any income you haven't paid tax on and other deductions, such as company benefits or the High Income Child Benefit Charge, then replaces the last digit with a letter.

GOV.UK's own example: someone with the standard £12,570 allowance gets medical insurance from their employer worth £1,570. That's taken off, leaving £11,000 tax-free, so their code is 1100L.

K codes work the other way. Multiply the number by 10 to see how much is added to your taxable income. On GOV.UK's example, someone with code K475 and a £27,000 salary has taxable income of £31,750 (£27,000 plus £4,750). The tax taken in each pay period can't be more than half of the pre-tax pay or pension. See if you have a K in your tax code.

Emergency tax codes: W1, M1 and X

You're on an emergency tax code if your code ends in W1 (paid weekly, for example 1257L W1), M1 (paid monthly, for example S875L M1) or X (pay dates vary, for example C663L X). Your payslip may say NONCUM instead. Normally your tax is worked out on your total income so far in the tax year. On an emergency code it's worked out on what you're paid in that week or month only, as if you were paid that amount every week or month of the year, so you could pay the wrong amount. 1257L on its own isn't an emergency code.

It usually happens when a new employer doesn't have your previous income details. Give them your P45 if you have one. HMRC normally updates your code once they have your details, which can take up to 35 days from when you start. You can also be put on an emergency code when you start getting company benefits or the State Pension. See emergency tax codes on GOV.UK.

Rates used by BR, D0, D1 and the S and C codes (2026 to 2027)

Sources: Income Tax rates, Income Tax in Scotland and Income Tax in Wales on GOV.UK, checked 23 October 2026. The standard Personal Allowance for 2026 to 2027 is £12,570, and it goes down by £1 for every £2 of adjusted net income over £100,000 (to zero at £125,140).

How to check your tax code

1. Find your code. It's on your payslip, in the HMRC app, on a Tax Code Notice letter if HMRC sends you one, or in HMRC's Check your Income Tax online service. You have a separate code for each job or pension.
2. Type it into the checker above. Include any letters before the number (S or C) and anything after it, such as W1, M1 or X. Spaces and lower case are fine.
3. Read the number. For most codes, the number times 10 is the tax-free pay you get from that job in the tax year. 1257L means £12,570, the standard Personal Allowance for 2026 to 2027. A K code is different: the number shows how much is added to your taxable pay.
4. Check it fits your situation. A lower number than 1257 is normal if you have company benefits, untaxed income or tax to pay back from an earlier year. BR, D0 or D1 is normal on a second job or pension. An emergency code (W1, M1 or X) is common for a few weeks after starting a new job.
5. If it looks wrong, update HMRC. Sign in to Check your Income Tax or the HMRC app and check your employment, pension, estimated income, company benefits and expenses. If you've left a job without a P45, ask your old employer for one. HMRC will tell you and your employer any new code within 15 working days. If you've just started a job, GOV.UK says to wait 35 days before contacting HMRC.

Common reasons a tax code changes

GOV.UK lists these, among others: you start a new job or get income from an extra job or pension; you get taxable state benefits or your State Pension changes; you start or stop getting company benefits such as a company car or medical insurance; your savings interest is more than your Personal Savings Allowance; you claim Marriage Allowance or tax relief on job expenses; you pay the High Income Child Benefit Charge through your wages; or you've been on the wrong code and owe tax. See why your tax code might change.

Paid too much or too little?

This checker explains your code. It doesn't work out your tax or any refund. If you've been on the wrong code, HMRC normally refunds overpaid tax through your pay once they have your income details, or collects tax you owe by adjusting your code. After the tax year ends, they write to you if you haven't paid the right amount. See if you've paid too much or too little tax. HMRC also has its own check what your tax code means tool.

Frequently asked questions

What does the tax code 1257L mean?
1257L is the tax code most people with one job or pension have. The number tells your employer how much tax-free income you get from that job: multiply it by 10, so 1257L means £12,570, the standard Personal Allowance for the 2026 to 2027 tax year. The L means you get the standard tax-free Personal Allowance.

How do I work out my tax-free allowance from my tax code?
Multiply the number in your code by 10. A code of 1100L means £11,000 of tax-free income from that job in the tax year. HMRC starts with your Personal Allowance and takes off things like untaxed income or company benefits, then replaces the last digit with a letter. K codes work the other way round: the number shows an amount added to your taxable pay.

What does S or C at the start of my tax code mean?
S means your income is taxed using the Scottish Income Tax rates, because your main home is in Scotland. C means it's taxed using the Welsh rates, because your main home is in Wales. For example, someone in Scotland with the standard Personal Allowance has the code S1257L.

What is an emergency tax code (W1, M1 or X)?
If your code ends in W1 (paid weekly), M1 (paid monthly) or X (pay dates vary), or your payslip says NONCUM, you're on an emergency tax code. Your tax is worked out on what you're paid in that week or month only, as if you were paid that amount every week or month of the year, so you could pay the wrong amount. It's usually temporary, for example when a new employer doesn't have your P45. HMRC can take up to 35 days from when you start a job to update it.

What do BR, D0 and D1 mean?
They're usually used for a second job or pension. BR means all your income from that job or pension is taxed at the basic rate, D0 at the higher rate and D1 at the additional rate, with no tax-free allowance from it. In Scotland SBR, SD0, SD1, SD2 and SD3 use the basic, intermediate, higher, advanced and top rates. In Wales the codes are CBR, CD0 and CD1.

What does a K tax code mean?
A K code means you have income or deductions, such as company benefits, State Pension or tax owed from an earlier year, that are higher than your tax-free Personal Allowance and aren't already being taxed. Multiply the number by 10 to see how much is added to your taxable pay: K475 adds £4,750. Your employer or pension provider can't take more than half of your pre-tax pay or pension in tax when using a K code.

What does 0T mean?
0T means you get no tax-free allowance from that job or pension, so tax is taken from all of it. It's used when your Personal Allowance has been used up, or when you've started a new job and your employer doesn't have the details they need to give you a tax code.

Why has my tax code changed, and what if it's wrong?
HMRC changes your code when your income or circumstances change, for example a new job, a second job or pension, company benefits, Marriage Allowance or tax owed from before. If you think it's wrong, sign in to HMRC's Check your Income Tax service or the HMRC app and update your details. HMRC tells you and your employer the new code within 15 working days. If you've paid too much or too little tax, HMRC sorts it out through your pay or a letter. This page doesn't work out refunds.

More pay tools

See your take-home pay with the take-home pay calculator, compare 36 salaries in the salary after tax tables, work out the tax on a bonus with the bonus tax calculator, check the £100,000 tax trap and the Child Benefit charge, or browse every pay and tax calculator on the Tax & Pay page.

Sources

GOV.UK: Tax codes, What your tax code means, Emergency tax codes, If you have a K in your tax code, Understanding your employees' tax codes, Income Tax rates and Personal Allowances, Income Tax in Scotland, Income Tax in Wales, Marriage Allowance. All checked on 23 October 2026. General guidance only, not tax or financial advice. HMRC sets your tax code; check it in Check your Income Tax or the HMRC app.