HMRC has sent out reminders to nearly one million individuals who are eligible for a tax refund. Last year, HMRC contacted these individuals after they had overpaid income tax, often due to errors in their tax code.

If you have overpaid tax, HMRC typically sends a P800 tax calculation letter with instructions on how to claim your refund. You can claim your refund online or receive a check by mail.

It is crucial to ensure your tax code is accurate as it determines the amount of tax deducted from your income. The most common tax code, 1257L, is used for individuals with one job or pension, but variations exist based on personal circumstances.

Mistakes in tax codes can occur for various reasons, such as starting a new job or providing incorrect income information to HMRC. To verify your tax code, review your latest payslip or P45 if you recently left a job.

If you believe you have overpaid tax and are owed a refund, contact HMRC at 0300 200 3300 or use the HMRC app to make a claim. Conversely, if you have underpaid tax, it is advisable to rectify the situation promptly to avoid accruing additional charges.