2025 / 26

UK Tax Code Checker

Enter your tax code to instantly understand what it means, your personal allowance, and what to do if it's wrong.

🔍 Enter Your Tax Code
Common codes: 1257L BR D0 S1257L K500 NT 1257L W1
Tax Code
1257L
Personal Allowance
£12,570
per year, tax-free
💡 What This Code Means
🔢
Letter
💰
Tax You'll Pay
❌

What To Do If Your Tax Code Is Wrong

Source: gov.uk/tax-codes

1
Check your tax code online
Sign in to the Check your Income Tax service at HMRC to see what information they hold about your income, benefits, and allowances.
🏛️ Check your Income Tax on GOV.UK →
2
Review and update your details
Check that your employment, pension, estimated taxable income, company benefits, and expenses are all correct. Update anything wrong or missing — this is the fastest way to fix a wrong code.
3
Wait for HMRC to update your code
If your tax code needs to change, HMRC will update it and notify you and your employer within 15 working days.
📬 Monthly paid: next/following payslip · Weekly paid: appears on your 3rd payslip
4
Claim a refund if you've overpaid
If a wrong tax code caused you to overpay, you can claim a refund — or HMRC may contact you if you've underpaid.
🏛️ Get a refund or pay what you owe →
💡
Tip: If you've just started a new job, wait 35 days before contacting HMRC — it takes time for them to receive new income details from your employer.
📞

How To Contact HMRC To Change Your Code

Source: gov.uk — HMRC contact

💻
Online — Fastest
Use your Personal Tax Account to check and update your tax code without waiting on hold.
🏛️ Sign in to Personal Tax Account →
You'll need a Government Gateway ID or GOV.UK One Login to access.
📞
By Phone
Speak to HMRC's Income Tax helpline for individuals and employees.
0300 200 3300
Mon–Fri 8am–6pm. Have your National Insurance number ready. Calls may be recorded.
✉️
By Post
Write to HMRC with your National Insurance number and details of the error.
Pay As You Earn and Self Assessment
HM Revenue and Customs
BX9 1AS
United Kingdom
Allow 15 working days for a response.
⚠️
Before you call: Have your National Insurance number, payslip, and tax code ready. This speeds up any query significantly.
📋

Common UK Tax Code Letters — Reference

Source: gov.uk — What your tax code means

Letter(s)MeaningPersonal Allowance?
LStandard Personal Allowance (most common code)Yes — standard
MReceived 10% of partner's allowance via Marriage AllowanceYes — increased
NTransferred 10% of your allowance to your partnerYes — reduced
TOther calculations apply; HMRC reviewing your affairsDepends
0TNo Personal Allowance — emergency code, new job without P45No
BRAll income taxed at 20% Basic Rate — common for second jobsNo
D0All income taxed at 40% Higher Rate — additional jobs/pensionsNo
D1All income taxed at 45% Additional RateNo
NTNo tax to pay on this incomeN/A
KNegative allowance — unpaid tax, taxable benefits (e.g. company car) added to your taxable incomeNegative
S prefixScottish taxpayer — Scottish Income Tax rates applyYes (Scottish)
C prefixWelsh taxpayer — Welsh rates of Income Tax applyYes (Welsh)
W1 / M1Emergency code — tax calculated per pay period, not cumulativelyTemporary

Understanding Your UK Tax Code

Your tax code is used by your employer or pension provider to work out how much Income Tax to take from your pay or pension. HM Revenue and Customs (HMRC) tells them which code to use. The UK Tax Code Checker tool helps you decode your tax code instantly so you know exactly what your Personal Allowance is and if you are on an emergency tax code.

The most common tax code for the 2025/26 tax year is 1257L. This means you have the standard tax-free Personal Allowance of £12,570.

What if my tax code is wrong?

If you think your tax code is wrong (for example, you are lacking a tax-free allowance or are on a W1/M1 emergency code unexpectedly), you could be paying too much or too little tax. You should contact HMRC directly or use your personal tax account online to update your employment details.

To see how your tax code affects your monthly pay packet, enter your salary and tax code into our Full UK Tax Calculator.