Tax code · 2026/27

K10 means £100 is added to your taxable pay

Tax code K10 is a K code. Instead of a tax-free allowance you get £100 a year added to your taxable income, £8 a month, so you pay tax on more than your salary. K codes are used when taxable benefits, untaxed income or tax owed from an earlier year are worth more than your personal allowance.

What does each part of K10 mean?

The number after the K is multiplied by 10 to give the amount added to your taxable pay each year: 10 × 10 = £100.
Common causes are company cars or medical insurance, state pension paid without tax deducted, or tax owed from an earlier year being collected through PAYE.
HMRC caps the deduction so no more than half of your pay in any period is taken as tax under a K code.
There is no S or C prefix, so HMRC treats you as living in England or Northern Ireland.

How much tax do you pay with code K10?

The table shows income tax and take-home pay in 2026/27 for four salaries with code K10, compared with the standard code 1257L. National Insurance is not affected by your tax code.

Salary	Tax with K10	Tax on standard code	Take-home with K10	Per month
£25,000	£5,020	£2,486	£18,986	£1,582
£35,000	£7,020	£4,486	£26,186	£2,182
£50,000	£12,500	£7,486	£34,506	£2,875
£75,000	£22,500	£17,432	£48,989	£4,082

On £35,000 the effective rate with K10 is 25.2%, against 17.9% on the standard code, a difference of £2,534 a year. Use the take-home pay calculator with your own salary, pension and student loan.

Frequently asked questions

Is tax code K10 correct for me?

K10 is correct if you have taxable benefits or untaxed income worth more than your personal allowance, or HMRC is collecting an underpayment. Compare the deductions in your Personal Tax Account with what you actually receive.

How much tax do I pay on £35,000 with tax code K10?

On £35,000 with code K10 income tax is £7,020 a year in 2026/27, leaving take-home pay of £26,186 (£2,182 a month) after National Insurance of £1,794. On the standard code it would be £4,486.

How do I change tax code K10?

You cannot change it yourself; only HMRC can issue a new code. Update your details in your HMRC Personal Tax Account or call 0300 200 3300 with your National Insurance number and details of your income and benefits. HMRC sends the new code to your employer and any tax overpaid in the year is refunded through your pay.

What does the lack of a prefix mean?

No prefix means HMRC treats you as living in England or Northern Ireland. If you actually live in Scotland or Wales, tell HMRC so the correct regional code can be issued.