What is a K tax code?
A K tax code means that your total allowances are less than your total ‘deductions.’ How the ‘K code’ works If your deductions (untaxed income on which tax is still due) are more than your allowances you’ll be given a K code, to ensure you pay tax on the excess. Whereas with other tax codes the number indicates the amount of income you can have tax-free, the number in a K code multiplied by ten broadly indicates how much must be added to your taxable income to take account of the excess untaxed income you received.