If you have opened a payslip and wondered what "1257L" means, or why your code has suddenly become "BR", "0T" or "K475", this guide is for you. Your tax code tells your employer or pension provider how much tax-free pay to give you before Income Tax is taken. A wrong code is one of the most common reasons people in the UK overpay or underpay tax, so it is worth understanding.
Once your code is right, you can check what you should take home with the free >UK Take-Home Pay Calculator.
1257L means you get the standard Personal Allowance of £12,570 tax-free in the tax year. Remove the letter and multiply the number by 10 and you get your allowance: 1257 × 10 = £12,570. The "L" means you are entitled to the standard tax-free Personal Allowance.
Source: >GOV.UK – Tax codes and >GOV.UK – What your tax code means.
1257L is the most common code in the UK for 2026/27. The Personal Allowance has been frozen at £12,570 since April 2021, and at Budget 2025 the government said Income Tax thresholds will stay frozen until April 2031 (>GOV.UK – Budget 2025).
Payroll spreads your allowance across the year:
Income Tax is charged only on pay above those amounts. In England, Wales and Northern Ireland the rates are 20% up to £50,270, 40% up to £125,140 and 45% above that. Scotland has its own bands (the code starts with "S"). See >GOV.UK – Income Tax rates and Personal Allowances.
Worked example. On a £30,000 salary with code 1257L, paid monthly:
National Insurance is worked out separately and does not use your tax code. For the full picture, see How much tax will I pay on my salary?.
The official list is on >GOV.UK – What your tax code means.
Some codes mean all of that income is taxed:
If you have one job and see BR or 0T, check it with HMRC. You may be paying far too much tax.
If your code ends in W1 (week 1), M1 (month 1) or X, you are on an emergency tax code, for example 1257L W1 or 1257L M1. Your employer works out your tax on each payday by itself, without counting what you have already earned and paid this tax year.
You usually get an emergency code when:
An emergency code is temporary. Once HMRC has the right details, it sends your employer the correct code, and any overpaid tax is usually refunded through payroll. Source: >GOV.UK – Emergency tax codes.
A K code, such as K475, means you have income that is not taxed at source, like a company car or untaxed state benefits, and it is worth more than your tax-free allowance. HMRC collects that tax through your pay instead.
K475 adds £4,750 to your taxable pay for the year. By law, a K code cannot make your employer take more than half of your pay in tax in any pay period.
HMRC can change your code during the year if:
Your employer cannot change your code itself. It has to use the code HMRC sends.
If you were on the wrong code, HMRC normally corrects it through your pay in the same tax year. For earlier years, you will receive a P800 calculation after the tax year ends, or you can >claim a refund on GOV.UK. Be careful of scam texts and emails offering "tax refunds". HMRC does not send refund links by text.
For most people with one job or pension and no company benefits, yes. It is the standard code for 2026/27.
It is an emergency code. You get the £12,570 allowance, but each month's tax is worked out separately. It usually stops once HMRC updates your record.
Your allowance is already used by your main job, so the second job taxes everything at 20%. If your main job pays less than £12,570, ask HMRC to split your allowance.
You get no tax-free allowance on that income. Check it with HMRC unless you earn over £125,140.
Yes. HMRC usually corrects it through payroll in the same year, or after the year ends with a P800 calculation.
You pay Scottish Income Tax. The allowance is the same £12,570, but the rate bands are different.
Checked against GOV.UK in October 2026. This is general information, not tax advice. Contact HMRC about your own situation.
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