HMRC reminds employers to check tax codes at start of new tax year

In its latest Employer Bulletin, HMRC highlights the importance of checking coding notices (P6 and P9) when they are received. These codes determine how much tax is deducted from employees and errors can lead to under- or overpayments. Although new codes apply from the start of the tax year, HMRC notes that those issued earlier may not include all adjustments. Further updates can follow once additional information is processed, meaning employees’ tax positions may change during the year.

Employers must apply coding notices promptly through payroll and ensure systems are updated for the new tax year. Failure to do so can result in incorrect deductions and additional work to correct errors later. The practical message is to treat coding notices as an active compliance step rather than a routine update. Unexpected changes should be reviewed and, where necessary, queried with HMRC or the employee to avoid ongoing issues.