Key facts (2026): Your tax code tells your employer how much tax to deduct from your pay. The most common code for the 2025–26 tax year is 1257L, representing the standard personal allowance of £12,570. An incorrect tax code means you overpay or underpay tax — check yours annually and especially when starting a new job.

HMRC estimates that millions of UK taxpayers have incorrect tax codes at any given time. An emergency tax code (used when HMRC does not have your details) is the most common cause of overpayment. Understanding what your code means — and acting quickly if it looks wrong — can save or recover hundreds of pounds.

How to Check Your Tax Code

Check your payslip — your tax code should appear on every payslip. Check your P60 (issued annually after the tax year ends). Log in to your Personal Tax Account at gov.uk/personal-tax-account — this shows your current code and allows you to update your details. If you have multiple jobs, each employer uses a separate code and you should check all of them.

What the Numbers and Letters Mean

The number in your tax code is your personal allowance divided by 10 — so 1257L means a £12,570 personal allowance, the standard amount for most people in 2025–26. The letter shows how the allowance is applied: L is the most common (standard personal allowance); M means you have received the Marriage Allowance transfer; N means you have transferred Marriage Allowance away; T means HMRC needs to review your code; BR means all income is taxed at basic rate (usually a second job); 0T means no personal allowance (emergency or zero allowance).

How to Fix a Wrong Tax Code

Contact HMRC via the Personal Tax Account online, by calling 0300 200 3300, or by writing. HMRC will update your code and issue a new one to your employer. If you have overpaid due to a wrong code, HMRC will calculate the refund and either send it directly or adjust your future deductions. You can claim back overpayments going back 4 tax years.

Our Verdict

Checking your tax code takes five minutes and is worth doing annually — particularly at the start of a new tax year, when starting a new job, or when your income changes. An emergency code (starting with 1257 on a week 1/month 1 basis) is the most common cause of significant overpayment. Act quickly if yours looks wrong — HMRC will correct it but you need to prompt them.

Frequently Asked Questions

How do I check my tax code UK?

Check your payslip, P60, or Personal Tax Account at gov.uk/personal-tax-account. You can also call HMRC on 0300 200 3300.

What is the standard tax code 2025-26?

1257L for most employees, representing the standard personal allowance of £12,570.

What does BR tax code mean?

BR means all income from that source is taxed at the basic rate (20%) with no personal allowance applied — usually applied to a second job or pension.

Disclaimer: For informational purposes only. Verify with gov.uk or qualified professionals before making decisions.

Last updated: April 2026 · Author: Chandraketu Tripathi