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Tax Code Checker UK — What Does My Tax Code Mean?

1257L is the standard code and means a £12,570 tax-free allowance. Multiply the number by ten to get your allowance.

Reference notes for the UK tax year 2026/27, computed from HMRC's published rates rather than copied from another site.

How it works

Code What it means
1257L standard £12,570 allowance
BR all income at basic rate, no allowance, typical second job
D0 / D1 all at higher / additional rate
K negative allowance, you owe more than you are allowed
S / C prefix Scottish / Welsh rates
M1, W1, X suffix emergency, non-cumulative
M / N suffix Marriage Allowance received / given

A K code is the one worth understanding. It means a taxable benefit or an underpayment exceeds your allowance, so an amount is added to your taxable pay rather than subtracted. There is a 50% limit: no more than half your pay can be taken as tax.

An emergency code corrects itself automatically once HMRC issues a proper one. You do not have to claim it back.

What this does not cover

A code that looks odd is usually correct and reflects something HMRC knows about your income. Check your Personal Tax Account before challenging it.

Use the calculator

Tax Code Checker UK →

Free, no sign-up, runs in your browser. Your figures are never sent anywhere.

Worked examples at real salaries

Full deduction breakdowns, computed on 2026/27 rates:

Salary Take-home a year Take-home a month
£25,000 after tax £21,519.60 £1,793.30
£40,000 after tax £32,319.60 £2,693.30
£60,000 after tax £45,357.40 £3,779.78
£100,000 after tax £68,557.40 £5,713.12

Related tools

Check the figures yourself

Related calculators on GitHub

Full index: UK Tax & Take-Home Pay Guide — twelve guides, twelve worked salary examples and a reference table covering the whole UK system.

Source and tax year

Figures are for the 2026/27 tax year, which runs 6 April 2026 to 5 April 2027, and were checked against gov.uk on 28 August 2026.

Rates change every April, and often at a Budget. Check the tax year a figure belongs to before relying on it.

Corrections

Found a wrong number? Open an issue with the figure and a gov.uk link. Tax errors are worth fixing quickly.

Licence

CC BY 4.0. Use it, quote it, fork it.

About

1257L is the standard code and means a £12,570 tax-free allowance. Multiply the number by ten to get your allowance.

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