Guide · Tax codes

UK tax codes explained

What the numbers and letters in your tax code mean, how to check it is right and how to fix a wrong code with HMRC. Start by it is on your payslip, P60, P45 or in your HMRC Personal Tax Account. It looks like 1257L, BR or K475.

By Uthman ChoudhuryPublished 20 September 2026Updated 20 September 2026

Skip the reading: use the Tax Code Explainer for your own numbers.

How do you check your tax code is right?

Find your code. It is on your payslip, P60, P45 or in your HMRC Personal Tax Account. It looks like 1257L, BR or K475.
Check the prefix. S means Scottish rates, C means Welsh rates, K means a negative allowance. No prefix means England or Northern Ireland.
Multiply the number by 10. This gives your annual tax-free allowance. 1257 means £12,570. For K codes it is the amount added to your pay.
Read the suffix. L is standard, M and N show Marriage Allowance, T means HMRC reviews it. BR, D0 and D1 are flat rates for second incomes. W1, M1 or X mean an emergency code.
Compare with the standard code. If yours differs from 1257L, the difference should match a benefit, expense or underpayment you recognise. If not, contact HMRC.

What is a tax code?

A tax code is a short instruction from HMRC to your employer or pension provider. It tells them how much of your pay to leave untaxed and, in some cases, which rate to apply. It does not tell them your total income or how much tax you should pay overall; it only controls what happens to this particular source of pay. Getting it wrong means you pay too much or too little through the year, though HMRC eventually reconciles it.

How do you read the number and letters?

Part	Meaning
Number	Allowance ÷ 10. 1257 means £12,570.
L	Standard personal allowance.
M / N	Marriage Allowance received (M, allowance +£1,260) or given (N, −£1,260).
T	HMRC reviews the code each year, often because of the £100,000 taper.
S / C prefix	Scottish or Welsh taxpayer.
K prefix	Negative allowance: number × 10 is added to taxable pay.
BR / D0 / D1	All pay at 20% / 40% / 45% (Scotland: SD0 21%, SD1 42%, SD2 45%, SD3 48%).
0T	No allowance but normal bands.
NT	No tax.
W1 / M1 / X	Emergency, non-cumulative.

Worked example: code 1100L with a company car

An employee with a company car worth £1,570 a year as a benefit in kind has the benefit deducted from their allowance: £12,570 − £1,570 = £11,000, giving code 1100L. On £40,000 they pay £5,800 income tax instead of £5,486 on 1257L, the extra £314 being 20% of the benefit.

What do people get wrong about tax codes?

Assuming the code is right because it came from HMRC. It is based on the information HMRC holds, which is often out of date.
Leaving BR on a former second job. If the main job ends, the remaining job needs the allowance moved to it.
Not telling HMRC about a move to or from Scotland. The S prefix follows your address, and being on the wrong one changes your tax.

Check any code with the tax code explainer or browse the 200 most common codes.

Frequently asked questions

What is the emergency tax code?

It is the standard code applied on a non-cumulative basis, shown as 1257L W1, 1257L M1 or 1257LX. You get the normal allowance each pay period but earlier periods are ignored, so refunds and underpayments are not corrected until HMRC issues a cumulative code.

Why has my tax code changed?

HMRC changes codes when your circumstances change: a new benefit, a second job, Marriage Allowance, a change of address to or from Scotland, or tax owed from a previous year. You should receive a P2 coding notice explaining it, or you can see the breakdown online.

Can I have two tax codes?

Yes, one per job or pension. Your personal allowance is normally set against your main job and the second source gets BR, D0 or D1. You can ask HMRC to split the allowance between two jobs if neither uses it fully.