Your tax code explained: 1257L, BR, 0T and emergency codes
The tax code tells payroll how much of your pay is tax-free. A wrong code is the most common reason a UK payslip is off, and you can fix it yourself in the HMRC app or your personal tax account.
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Reading the code
Multiply the number by 10 to get your tax-free allowance for the year: 1257L means 12,570 GBP. L is the standard personal allowance. An S prefix means Scottish rates, C means Welsh rates. M and N relate to the Marriage Allowance. A K code means your untaxed income and benefits (a company car, for example) are bigger than your allowance, so an amount is added to your pay; tax under a K code is capped at half of your pay in the period.
Codes with no allowance
BR taxes everything at 20%, D0 at 40%, D1 at 45%, and 0T gives no allowance but uses the normal bands. NT means no tax. BR is normal for a second job, because the allowance is already used in your main job. On your main or only job, these codes almost always mean you are overpaying.
Emergency codes
W1, M1 or X after the code means it is applied to each pay period on its own instead of cumulatively, so tax overpaid earlier in the year is not given back. Payroll uses an emergency code (from 6 April 2026: 1257L W1, M1 or X) when you start without a P45 or HMRC has not yet sent your code. It should last a month or two at most.
How to fix it
Open the HMRC app or your personal tax account, check the employer, income and benefits HMRC has on file, and correct anything wrong or out of date (an old job still listed, a benefit you no longer have). HMRC sends the new code to your employer, usually within a few weeks. Once a cumulative code is in place, the overpaid tax for the current year comes back through payroll. For earlier years, HMRC reconciles after the tax year ends and you can claim the refund in your account.
Check your own payslip. Upload it and every line is explained, the rates verified and the questions for HR written for you. Free, nothing stored. Decode my payslip
Questions people ask
My code is lower than 1257L, for example 1100L. Why?
HMRC has reduced your allowance to collect tax on something it knows about: a benefit in kind such as private medical insurance, untaxed interest or other income, or tax you underpaid in an earlier year. Your personal tax account lists the reasons.
I have two jobs. Can I move part of my allowance to the second one?
Yes. If your main job pays less than 12,570 GBP a year, ask HMRC to split the allowance between the jobs, and the second job gets a code with an allowance instead of BR.
Related guides
Indicative rules as of October 2026. Not tax or legal advice.