Tax Code Calculator & Checker 2026/27
Your tax code tells your employer how much of your pay is tax-free. Enter your code and salary to decode it, see your allowance and check the tax looks right for 2026/27.
Last updated 4 July 2026 · Written and reviewed by Mustafa Bilgic
Tax code calculator
Decode a UK tax code and estimate the tax.
Guide only — check your code on GOV.UK or the HMRC app.
What your tax code means
Your tax code is the short string of numbers and letters on your payslip that tells your employer or pension provider how much tax to take. In most cases the numbers stand for your tax-free allowance divided by ten: the standard 2026/27 code 1257L means £12,570 tax-free — the full personal allowance — before 20% tax starts. The letter explains your situation, and a few special codes change the sum entirely.
1257L gives you £12,570 tax-free. BR taxes all your pay at 20% with no allowance (normal for a second job). 0T gives no allowance at all. A K code is the reverse — it adds to your taxable pay to collect tax on untaxed income or benefits.
What the letters mean
| Code | What it means |
|---|---|
| L | Standard personal allowance (e.g. 1257L = £12,570 tax-free) |
| M | You've received 10% of a partner's allowance (Marriage Allowance) |
| N | You've given away 10% of your allowance to a partner |
| T | Other calculations are involved in your allowance |
| 0T | No personal allowance — every pound is taxed |
| BR | All income taxed at basic rate (20%) — often a second job |
| D0 | All income taxed at higher rate (40%) |
| D1 | All income taxed at additional rate (45%) |
| NT | No tax is taken at all |
| K | Untaxed income is greater than your allowance — the number is added to your taxable pay |
How K codes work
A K code is the mirror image of a normal code. Instead of giving you tax-free pay, it adds an amount to your taxable income — used when you owe tax on things like a company car, the State Pension or unpaid tax from an earlier year. K475 adds £4,750 to what you're taxed on. There's a safeguard: an employer can never take more than half your pay in tax because of a K code. If you have a taxable company car, our company car tax calculator shows the benefit figure that often drives a K code.
W1, M1 and X — emergency codes
A code ending in W1, M1 or X is an emergency (non-cumulative) code. It taxes each pay period in isolation rather than across the year, which often happens when you start a new job before HMRC has your full details. It usually corrects to a normal cumulative code once your P45 or a starter checklist is processed, and any over- or under-payment is put right. If it lingers, contact HMRC.
Checking your code is right
An incorrect code is one of the most common reasons people overpay or underpay tax. Reasons to double-check: you have only one job but a BR or 0T code; you changed jobs recently; you have more than one source of income; or your code changed after a benefit or expense claim. You can view and update your code free in the HMRC personal tax account. If a wrong code has cost you money, HMRC will usually refund it or adjust future codes. To see how the resulting allowance flows through to your pay, use our take-home pay calculator.
Frequently asked questions
What does the 1257L tax code mean?
1257L is the standard tax code for 2026/27. The 1257 means you have £12,570 of tax-free personal allowance (the number times ten), and the L means you get the standard allowance. Above £12,570 you pay 20% basic-rate tax, then 40% and 45% on higher slices.
What does a BR tax code mean?
BR means Basic Rate — all the income from that job or pension is taxed at 20% with no tax-free allowance applied. It's normal for a second job or pension where your allowance is already used against your main income. If it's on your only job, check it with HMRC.
What is a K tax code?
A K code means the tax due on untaxed income or benefits — such as a company car or unpaid tax — is more than your tax-free allowance. The number is added to your taxable pay rather than deducted from it. Your employer can never take more than half your pay through a K code.
How do I know if my tax code is wrong?
Signs of a wrong code include a BR or 0T code on your only job, a code that didn't update after a job change, or an unexpected change. Check the personal allowance is £12,570 unless you earn over £100,000. You can review and correct your code in your HMRC personal tax account.
What does W1 or M1 after my tax code mean?
W1 (week 1) and M1 (month 1) are emergency codes that tax each pay period on its own rather than cumulatively across the year. They're common when starting a new job and usually correct automatically once HMRC has your full details, with any overpaid tax refunded.