Think your tax code is wrong?
A wrong tax code can make you pay too much or too little Income Tax through PAYE. The fastest route is to compare your payslip with the employment, pension, income and benefit details HMRC is using.
Signs your tax code may need checking
Unexpected BR, D0 or D1 codes, a W1/M1/X suffix after you expected a normal cumulative code, a code change after changing jobs, or a code that appears to include the wrong benefits or untaxed income are all reasons to check.
What HMRC says to update
HMRC says wrong tax codes are usually caused by incorrect or missing information. Check your jobs, pensions, estimated annual income and taxable benefits and update anything that is wrong.
What happens if you paid too much?
If HMRC changes your code during the year, a later cumulative payroll calculation can sometimes repay excess tax automatically. If the position is not corrected in-year, HMRC can reconcile it after the tax year.
What happens if you paid too little?
HMRC may adjust your tax code to collect underpaid tax over time where possible, or contact you after checking the year-end position. A tax code changes PAYE deductions but does not change the underlying tax you owe on total taxable income.
Related NetSlip tools & guides
FAQs
Can my employer fix my tax code?
Your employer applies the code HMRC provides. If the underlying information is wrong, you normally need to update HMRC.
Why did my tax code suddenly change?
HMRC can change a code when it receives new information about jobs, pensions, benefits, untaxed income or earlier tax.
Will I automatically get overpaid tax back?
Sometimes a corrected cumulative code repays it through payroll. Otherwise HMRC can reconcile the position after the tax year.