Tax Code Calculator UK

Your tax code tells your employer how much tax-free Personal Allowance to apply before calculating your Income Tax. The most common code, 1257L, means you get the standard £12,570 Personal Allowance for 2026/27. Letters and other numbers indicate variations — use the calculator above to check yours.

BR means all your income is taxed at the basic rate (20%) with no Personal Allowance — common for second jobs. D0 means all income is taxed at the higher rate (40%). D1 means all income is taxed at the additional rate (45%). These are typically used when HMRC has already allocated your Personal Allowance to another source of income.

A K tax code is used when your total deductions (such as company benefits or previous unpaid tax) exceed your Personal Allowance. Instead of reducing your tax, it adds the excess to your taxable income, meaning more tax is deducted than the standard calculation would suggest.

Emergency tax codes (shown as 1257L W1, 1257L M1, or 1257L X) are used when HMRC doesn't yet have full information about your income — often when starting a new job. They calculate tax non-cumulatively for each pay period, which can sometimes result in too much tax being withheld temporarily.

Compare your tax code to your circumstances: if you have one job, no benefits and no untaxed income, 1257L is likely correct. Check your payslip, P60 or HMRC's online Personal Tax Account. If something looks wrong, contact HMRC directly.

Yes. HMRC can update your code if your circumstances change — for example, a new job, company benefits, or correcting a previous under or overpayment of tax. Always check your payslip when your tax code changes.