What Does Your Tax Code Mean?
Your tax code tells your employer or pension provider how much of your pay can be treated as tax-free before Income Tax is calculated. For most people with one job in 2026 to 2027, code 1257L matches the standard £12,570 Personal Allowance. Wrong codes can mean too much or too little tax taken through PAYE, so it is worth checking yours against your circumstances.
Codes sit alongside the wider Income Tax bands for England, Wales and Northern Ireland. Savings interest may be taxed separately if it exceeds your Personal Savings Allowance. Use the tax hub to find related guides, including Marriage Allowance when one partner transfers part of their allowance.
Where to find your tax code
HMRC issues a code for each job or pension you have. Your employer or pension provider must use the code HMRC sends them.
You can find your code on your payslip, on a Tax Code Notice from HMRC, or by signing into the Check your Income Tax service online or in the HMRC app. If you have more than one source of pay, each may show a different code.
What the numbers mean
The numbers show how much income from that employment or pension is tax-free in the current tax year. HMRC usually starts from the Personal Allowance (£12,570 in 2026 to 2027), then reduces it for things like company benefits or the High Income Child Benefit Charge.
GOV.UK gives an example: if your allowance is £12,570 but you have £1,570 of medical insurance as a taxable benefit, the tax-free amount becomes £11,000. HMRC drops the last digit and adds a letter, giving code 1100L.
Only one job should normally use your full allowance. A second job often carries a code such as BR, meaning all income from that source is taxed at the basic rate.
What the letters mean
The letter explains how the allowance is being used. Common letters on GOV.UK include:
- L – you receive the standard tax-free Personal Allowance
- M – you have received 10% of your partner’s allowance (Marriage Allowance)
- N – you have transferred 10% of your allowance to your partner
- BR – all income from this job or pension is taxed at the basic rate (often a second job)
- D0 – all income taxed at the higher rate
- D1 – all income taxed at the additional rate
- 0T – your allowance is used up or your employer does not have enough details
- K – you have income you are not paying tax on that is more than your Personal Allowance
- NT – no tax is deducted from this source
- S – you are a Scottish taxpayer (Scottish rates apply)
- C – you are a Welsh taxpayer
- T – your tax code includes other calculations to work out your Personal Allowance
Emergency codes
If HMRC does not know your full income history, you may get an emergency tax code. These often end in W1, M1 or X, or are marked NONCUM (non-cumulative).
Emergency codes are common when you start a new job and your new employer has not yet received a full picture of your income.
Why your tax code changes
Codes are not fixed for life. GOV.UK lists reasons they may change, including:
- starting a new job
- taxable company benefits such as private medical insurance
- taking on an extra job or pension
- savings interest above your Personal Savings Allowance
- claiming or stopping Marriage Allowance
- claiming expenses relief for your job
- paying the High Income Child Benefit Charge through PAYE
Any of these can shift the tax-free amount HMRC expects your employer to use.
If your code is wrong
If you think your code is wrong, use the Check your Income Tax service to review and update your details. Ask for a P45 from your previous employer if you are missing employment history.
After HMRC processes a change, it usually updates you and your employer within 15 working days. If you are paid monthly, the new code may appear on your next payslip or the one after. Weekly paid employees may see the change on their third payslip after the update.
If you have just started a new job, GOV.UK suggests waiting 35 days before contacting HMRC about your code, so your record can catch up.
Frequently asked questions
Where can I see my tax code?
Check your payslip, a Tax Code Notice from HMRC, or your personal tax account online or in the HMRC app.
What does the number in my code mean?
It is your tax-free amount for that job or pension, with the last digit dropped. HMRC starts from the Personal Allowance, adjusts for untaxed income and benefits, then adds a letter.
What is an emergency tax code?
Codes ending W1, M1 or X, or marked NONCUM, are emergency codes used when HMRC lacks full details, such as when you start a new job.
How long does HMRC take to fix a code?
After you update your details, HMRC usually tells you and your employer within 15 working days. Monthly paid staff may see the change on the next or following payslip.
What do M and N mean on a tax code?
M means you have received 10% of your partner's Personal Allowance through Marriage Allowance. N means you have transferred 10% to your partner.
Sources
Disclaimer: This article is general information and not personal financial, tax or legal advice. Check your own situation with HMRC, GOV.UK or a regulated adviser.