HMRC Tax Code Checker

Type your tax code to check what it means: the tax-free allowance it gives you, what each letter and number stands for, and the problems it may be signalling. Add your salary and the checker also shows how much more or less tax the code takes than the standard 1257L. Free, with nothing to sign up for.

Your tax code

Exactly as it appears on your payslip or Tax Code Notice — for example 1257L, 1257L W1, BR, D0, NT, 0T, K475 or S1257L.

Your salary for the year (£, optional)

Add it to see how much more or less tax this code takes than the standard 1257L on the same pay.

Private by design: everything is worked out in your browser. Nothing you type here is sent to a server, stored or tracked.

1257L

£12,570.00 tax-free

The standard tax code: the full Personal Allowance, and the code most people with one job or pension have.

1257: The number is your tax-free income for the year in tens of pounds: 1257 means £12,570.00 you can earn from this job or pension before Income Tax starts. (HMRC builds the number by taking your tax-free amount and replacing its final digit with a letter.)
L: You're entitled to the standard tax-free Personal Allowance.

On a salary of £30,000.00

Income Tax under 1257L£3,486.00 a year

Income Tax under the standard 1257L£3,486.00 a year

Difference£0 — the same

Opens your browser's print view with a clean summary of this calculation — choose “Save as PDF” there to keep a copy.

How to use this tax code checker

Copy the code exactly as it appears on your latest payslip or Tax Code Notice — including any letter in front (S for Scotland, C for Wales) and any ending such as W1, M1 or X. The verdict explains the code part by part in plain words, flags the situations that usually mean a code is wrong, and — once you add a salary — puts a yearly and monthly figure on the difference between your code and the standard 1257L. Nothing leaves your browser at any point.

How tax codes work

Your tax code is the instruction HMRC gives your employer or pension provider so they take the right amount of Income Tax from each payment. You have a separate code for every job or pension. To build yours, HMRC starts with your tax-free Personal Allowance and takes off anything that reduces it — income you have not paid tax on, such as untaxed interest or part-time earnings, and other deductions such as company benefits or tax you owe — then replaces the final digit of the remaining amount with a letter.

The numbers are the tax-free amount in tens of pounds: 1257 means £12,570.00 a year before tax starts. The letter says why you get that amount: L is the standard allowance, M and N are Marriage Allowance (received / transferred), and T means HMRC has other calculations to check. Some codes have no numbers at all: BR, D0 and D1 tax everything at one flat rate, NT takes no tax, 0T gives no allowance, and a K code works in reverse — its number is added to your taxable pay. The prefix and suffix matter too: S means Scottish rates apply and C means Welsh rates, while W1, M1 and X endings mean an emergency code.

Common tax codes and what they mean

Tax code	What it means	Effect
1257L	The standard code: you're entitled to the standard tax-free Personal Allowance. Most people with one job or pension have it.	£12,570.00 tax-free
1383M	Marriage Allowance received: your partner transferred £1,260 of their Personal Allowance to you, on top of your own.	£13,830.00 tax-free
1131N	Marriage Allowance transferred: you've given £1,260 of your Personal Allowance to your partner.	£11,310.00 tax-free
1100L	A reduced allowance: HMRC has taken deductions off your Personal Allowance — in GOV.UK's example, a £1,570 company medical benefit turns 1257L into 1100L.	£11,000.00 tax-free
1257L W1 / 1257L M1	An emergency code: the same allowance as 1257L, but each pay day is taxed on its own (W1 = weekly pay, M1 = monthly) instead of on the year so far. The X ending is the same idea for irregular pay dates.	£12,570.00 tax-free, per-pay-day basis
0T	Your Personal Allowance has been used up, or you've started a new job and your employer doesn't yet have the details to give you a code.	Nothing tax-free
BR	All income from this job or pension is taxed at the basic rate — usually a second job or pension.	No allowance; everything at 20%
D0	All income from this job or pension is taxed at the higher rate — usually a second job or pension where your main income already uses the basic-rate band.	No allowance; everything at 40%
D1	All income from this job or pension is taxed at the additional rate.	No allowance; everything at 45%
NT	No tax is taken from this income.	No tax deducted
K475	A K code (example): the untaxed income or deductions in the code are worth more than your whole Personal Allowance, so an amount is added to your taxable pay instead.	£4,750.00 added to taxable pay
S1257L	The Scottish standard code: the S means this income is taxed using the rates in Scotland, which Scotland sets separately.	£12,570.00 tax-free, Scottish rates
C1257L	The Welsh standard code: the C (for Cymru) means this income is taxed using the rates in Wales.	£12,570.00 tax-free, Welsh rates

Meanings follow HMRC's own guide to tax codes on GOV.UK. Scotland also has flat-rate codes with no equivalent elsewhere — SBR, and SD0 to SD3 for its intermediate, higher, advanced and top rates — which the checker above decodes.

Worked example: one salary, three codes

On a £30,000.00 salary	Tax-free allowance	Income Tax for the year	Vs 1257L
1257L (standard)	£12,570.00	£3,486.00	—
1100L (reduced allowance)	£11,000.00	£3,800.00	£314.00 more
BR (no allowance)	None	£6,000.00	£2,514.00 more (£209.50 a month)
K475 (negative allowance)	−£4,750.00 (added to taxable pay)	£6,950.00	£3,464.00 more

BR is the right code for a second job — but on a £30,000.00 main job it would take £2,514.00 a year more tax than 1257L, because the whole Personal Allowance goes unused. (0T gives the same total as BR at this salary: both take 20% of everything. They part company on higher pay — 0T moves into the 40% band like a normal code, BR stays at 20%.) National Insurance is not part of the comparison: it does not depend on your tax code. The same salary run through our take-home pay calculator shows the full picture, tax and National Insurance together.

Where to find your tax code

Four places, quickest first in practice: your payslip — the code is printed on every payslip, next to your pay details; our payslip generator shows exactly where it sits on the document. HMRC's online service — sign in to Check your Income Tax to see your current code (and previous years'), or use the HMRC app. A Tax Code Notice — the letter HMRC sends when your code changes. And if you have more than one job or pension, remember each one has its own code: check them all, because the allowance can only sit on one.

What to do if your tax code is wrong

A wrong code almost always means HMRC holds wrong or missing information about you — employers cannot change your code themselves, so the fix runs through HMRC:

Sign in to Check your Income Tax (through your personal tax account or the HMRC app) and look at what HMRC has: your employments and pensions, your estimated taxable income, company benefits and expenses.
Update anything that is wrong or missing — a job you have left, a benefit that has stopped, an income estimate that is too high or too low.
HMRC issues the new code to you and your employer, normally within about 15 working days. It should show on your next or the following monthly payslip (the third weekly one).
Tax already overpaid is usually refunded through your pay once the new code is used; tax underpaid is collected by adjusting a future code, normally spread over a year or more.

If you cannot use the online service, contact HMRC through Income Tax enquiries. One exception to acting fast: if you have just started a new job, GOV.UK advises waiting 35 days before contacting HMRC, so your new income details have time to reach them — an emergency code in the first weeks of a job usually corrects itself.

Rates behind the comparison

Rate	Amount
Personal Allowance (code 1257L)	£12,570.00 (reduced by £1 per £2 of income over £100,000.00)
Basic rate (BR)	20% — on the first £37,700.00 of taxable income under a normal code
Higher rate (D0)	40% up to £125,140.00 of income
Additional rate (D1)	45% on income over £125,140.00
Employee National Insurance	8% from £12,570.00 to £50,270.00, then 2% — not affected by your tax code

Two honest limits. First, the comparison is against the standard 1257L on the same salary — your right code depends on everything you earn and receive, so a difference here shows what the code costs, not by itself that the code is wrong. Second, Scotland sets its own income tax bands: this checker decodes Scottish (S) codes in full, but its figures use the England, Wales and Northern Ireland bands, and it says so on the result rather than inventing Scottish figures.

Rates: 2026/27 rates — verified against GOV.UK (England, Wales and Northern Ireland). Last verified: 7 November 2026. Tax code meanings checked against GOV.UK's “Tax codes” guide on 9 November 2026.

Frequently asked questions

What does tax code 1257L mean?

The numbers in a tax code are your tax-free Personal Allowance in tens of pounds: 1257 means £12,570 a year you can earn before Income Tax starts. The letter shows why you get that allowance — L means you are entitled to the standard Personal Allowance. 1257L is the code most people with one job or pension have; HMRC builds it by taking your tax-free amount and replacing its final digit with a letter.

What is an emergency tax code (W1, M1 or X)?

You're on an emergency tax code if your code ends in W1 (paid weekly), M1 (paid monthly) or X (pay dates vary) — some payslips print NONCUM instead. Normally your tax is worked out on everything you've earned in the tax year so far; on an emergency code each pay day is taxed on its own, as if that week's or month's pay were your pattern for the whole year, which can take too much tax. It usually happens when you start a new job without a P45 from the old one, and it is normally temporary: HMRC updates your code once it has your full details, which can take up to 35 days from starting.

What does a K tax code mean?

A K code means the income you are not paying tax on — or the deductions in your code — are worth more than your entire Personal Allowance, so instead of a tax-free amount, the number in the code (in tens of pounds) is added to your taxable pay. Common causes: tax owed from a previous year being collected through your wages, the State Pension or other taxable benefits, company benefits such as a company car, or savings interest above your Personal Savings Allowance. Your employer cannot take more than half of your pre-tax pay in one pay period under a K code.

Where can I find my tax code?

In four places: on your payslip (it's printed on every one — our payslip generator shows where it sits); on a Tax Code Notice letter from HMRC, if you get one; in the HMRC app; or by signing in to HMRC's Check your Income Tax service, which shows your code for the current year and previous years. You get a separate tax code for each job or pension you have.

What should I do if my tax code is wrong?

Check and update the details HMRC holds about you — that is what the code is built from. The quickest route is HMRC's Check your Income Tax service: sign in, and check your employment, pension, estimated taxable income, company benefits and expenses, correcting anything wrong or missing. HMRC then updates your code and tells you and your employer within about 15 working days; it should appear on your next or the following monthly payslip (the third weekly one). If you've overpaid, the difference is usually refunded through your pay once the new code is used. If you can't use the online service, contact HMRC's Income Tax enquiries — but if you've just started a job, wait 35 days first so HMRC has your new income details.