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Tax Code Checker UK: What Does My Code Mean?
Enter your code to decode it, check your tax-free allowance and see the standard code for your salary.
Last updated: 25 October 2026
Find it on your payslip, P60 or HMRC coding notice.
Used to work out the standard code for your income and the estimated tax on this code.
How to read a code
Number × 10 = tax-free allowance. The letter explains your situation: L standard, M/N Marriage Allowance, BR all basic rate, 0T no allowance, K negative allowance, S Scotland, C Wales.
Your code
1257L
Personal allowance: £12,570 (standard personal allowance)
What should my code be?
On £40,000 in England & Northern Ireland, the standard code is 1257L (£12,570 tax-free).
This matches the standard code for your salary and region.
This is the standard code before company benefits, work expenses, Marriage Allowance, untaxed income or an underpayment from an earlier year. Above £100,000 the Personal Allowance tapers by £1 for every £2 earned, so the expected code falls; above £125,140 it reaches 0T.
Estimated tax on £40,000
Common UK tax codes
| Code | What it means | Tax-free amount |
|---|---|---|
| 1257L | Standard code for most employees | £12,570 |
| BR | All income taxed at basic rate 20% | £0 |
| 0T | No personal allowance | £0 |
| D0 | All income taxed at higher rate 40% | £0 |
| D1 | All income taxed at additional rate 45% | £0 |
| NT | No tax deducted | — |
| K475 | £4,750 added to taxable income | Negative |
| S1257L | Scottish standard code | £12,570 |
| C1257L | Welsh standard code | £12,570 |
| 1257L W1 / M1 | Emergency week 1 / month 1 basis | £12,570 annualised |
Based on HMRC guidance for the 2026/27 tax year. Your code can include adjustments for benefits, expenses, untaxed income or an underpayment, so always check your coding notice.
Official HMRC sources
Check your code directly with HMRC: what your tax code means and check your Income Tax in the HMRC app or Personal Tax Account.
Reviewed against HMRC guidance, 25 October 2026.
UK Tax Calculator
See your take-home pay after tax, NI, pension and student loan
UK Tax Codes Explained
What every letter and number means, and how to fix a wrong code
Understanding Your Payslip
Where your tax code, NI, pension and loan deductions appear
Frequently Asked Questions
What should my tax code be?
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For most employees in 2026/27 the standard code is 1257L — £12,570 tax-free. Scottish taxpayers use S1257L and Welsh taxpayers use C1257L. Your code can legitimately differ if you have company benefits, work expenses, untaxed income, an underpayment from a previous year, or Marriage Allowance. If none of those apply and your code is not 1257L, check it with HMRC.
What does 0T mean on my payslip?
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0T means you have no personal allowance, so tax is charged from the first pound you earn. It is common when you start a job without a P45, when HMRC does not yet know your income, or when your allowance has already been used by another job or pension. 0T is often an emergency code and should be corrected once HMRC has your details.
What does BR mean?
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BR means all income from that source is taxed at the basic rate of 20%, with no personal allowance applied. It is usually correct on a second job or a pension because your allowance is already used against your main job. If BR is on your only job, you are probably overpaying and should contact HMRC.
What does the number in my tax code mean?
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Multiply the number by 10 to get your tax-free allowance for the year. 1257L means £12,570 tax-free. 1000L means £10,000 tax-free. A lower number means less of your income is tax-free, usually because of benefits, expenses or an underpayment.
What is a K tax code?
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A K code is a negative allowance. Instead of giving you tax-free income, the number multiplied by 10 is added to your taxable income. K codes usually appear when untaxed income such as company benefits or unpaid tax from an earlier year is more than your personal allowance. Your employer cannot take more than 50% of your gross pay in tax because of a K code.
What does W1 or M1 mean on my tax code?
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W1 (week 1) or M1 (month 1) means your tax is worked out on that pay period alone, not cumulatively across the tax year. It is an emergency basis, often used when you start a new job mid-year or HMRC is waiting for information. It is usually temporary and can lead to an overpayment or underpayment until it is removed.
What is S1257L or C1257L?
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The S prefix means you pay Scottish income tax rates, which have more bands than the rest of the UK. The C prefix means you pay Welsh income tax rates. The number and letter after the prefix work the same way: 1257L means £12,570 tax-free. If you have moved between Scotland, Wales and England, tell HMRC so your prefix matches your address.
How do I fix a wrong tax code?
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Check your coding notice in the HMRC app or your Personal Tax Account at tax.service.gov.uk. You can update your income, benefits or expenses there, and HMRC will send a new code to your employer. You can also call HMRC on 0300 200 3300. Any overpaid tax is normally refunded through PAYE once the correct code is applied.
How much can a wrong tax code cost me?
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On a £40,000 salary in 2026/27, the standard 1257L code gives about £5,486 of income tax. A 0T code costs about £7,540 — around £2,054 more. A BR code costs about £8,000 — around £2,514 more. National Insurance is not affected by your tax code, and HMRC refunds overpaid tax once the code is corrected.