Your tax code tells your employer how much of your pay is tax-free. Most people never look at theirs — worth a quick check, since an incorrect one is one of the most common reasons people overpay or underpay tax without realising.
The standard code: 1257L
1257L is the code almost everyone should have in 2026/27. The numbers represent your £12,570 tax-free Personal Allowance; the L means you’re entitled to the standard allowance with no adjustments.
When it’s different
A K code means you owe tax from a previous year and it’s being clawed back through your pay. BR means everything is taxed at the basic 20% rate with no tax-free allowance at all — common on a second job. 0T means no allowance and tax charged at all applicable rates, often a temporary code while HMRC sorts out your details. D0 and D1 tax everything at the higher or additional rate respectively.
What to do if yours looks wrong
Check it against your P60 or latest payslip. If it doesn’t match what you’d expect, contact HMRC directly — it’s usually a five-minute fix, and getting it corrected sooner means less to unwind later.
How to actually check your tax code is correct
Your tax code appears on every payslip, your P60, and in your HMRC Personal Tax Account online. Compare it against what you’d expect given your circumstances — if you have one job, no benefits-in-kind, and no historic tax owed, 1257L is what you should normally see.
Frequently asked questions
Can my tax code change during the year?
Yes — HMRC updates it whenever your circumstances change, such as starting a benefit-in-kind, taking a second job, or repaying tax owed from a previous year.
What if I’ve been on the wrong code for months?
HMRC will usually correct it automatically once notified, and any overpaid tax is refunded through your pay, or underpaid tax collected via an adjusted code going forward.