HMRC is currently carrying out its annual reconciliation of PAYE for the 2025-26 tax year. Between June and November, HMRC calculates the Income Tax paid by individuals and checks whether the correct amount has been collected. Where HMRC identifies a difference, it may issue a tax calculation letter, known as a P800.

If you receive a P800, do not automatically accept that HMRC’s calculation is correct. You should check the figures against your own records, including your employment and pension income, tax deducted and any other relevant income or tax reliefs. Errors or missing information can affect the calculation and could result in either too much or too little tax being shown as due.

HMRC provides an online service that allows taxpayers to check how much Income Tax they paid for the year ended 5 April 2026. The calculation can also be checked through the HMRC app.

A P800 may show that you have overpaid tax and are due a refund, or that you have underpaid and need to pay additional tax. In some cases, the P800 will allow you to claim a refund or pay the tax owed online.

If you are unsure whether the figures or tax calculation are correct, we can review your P800 and advise whether any action is needed.