Millions of individuals are advised by HMRC to watch for an important tax notification this summer. If you are on PAYE and have either overpaid or underpaid taxes for the 2025/26 tax year, you will be sent a P800 letter. Various factors, such as an incorrect tax code, recent job changes, or commencing pension claims, could lead to inaccuracies in your tax bill.

Following the end of each tax year, HMRC reviews its PAYE records to ensure the accurate payment of Income Tax on earnings or pensions. P800 letters, distributed in batches until March 2027, will detail how to claim a refund in case of overpayment. Refunds can typically be claimed online or through a mailed cheque.

The most prevalent tax code, 1257L, is assigned to individuals with one job or pension, although not everyone will have this code. To locate your tax code, refer to your latest payslip or P45 if you recently left your job. In cases of underpaid tax, repayment to HMRC is necessary to avoid a larger debt accumulation.

Marc Gill, Director of Personal Tax Operations, emphasized the importance of timely refunds for those who have overpaid taxes. If you receive a P800 letter, follow the provided instructions to claim your refund via GOV.UK or the HMRC app, a quick and simple process.