Your tax code is a short mix of numbers and letters on your payslip. It tells your employer how much Income Tax to take from your pay through PAYE.
Get it right, and you’ll usually pay the correct tax across the year. Get it wrong, and you could be overpaying or facing a bill later.
This is general information, not personal tax advice. Tax rules can change and depend on your individual circumstances.
How to read it
- Numbers = your tax-free allowance
Multiply by 10 to get the amount you can earn before paying tax.
Example: 1257 = £12,570 tax-free. - Letters = your situation
They tell HMRC how to apply tax based on your circumstances.
Common tax codes
- 1257L – the standard code for most people with one job
- BR – all income taxed at basic rate (often a second job)
- D0 / D1 – all income taxed at higher or additional rate
- 0T – no tax-free allowance
- K – you owe tax from elsewhere, so you pay more
- W1 / M1 / X – emergency tax codes, often temporary
Why your code might change
- You start or leave a job
- You have more than one income
- Your pay or benefits change
- HMRC corrects a previous underpayment or overpayment
Why it matters
Your tax code directly affects your take-home pay. If it’s wrong, you might not notice straight away, but it adds up over time.
What to do
Check your code regularly on your payslip or HMRC account. If it looks off, contact HMRC. It’s your responsibility to flag it.
