What is a P800 letter?

A P800 is a tax calculation from HMRC. It tells your employee if they’ve overpaid or underpaid income tax.

This happens when the tax collected through PAYE doesn’t match HMRC’s final calculation for a given tax year.

The letter explains the difference and what action the employee needs to take.

Who receives the P800 letter?

The employee receives this letter, not the employer.

When are P800 letters sent?

HMRC usually sends P800 letters after they review their PAYE records after the end of a tax year.

Employees can start receiving letters between June and March of the following year. 

How to help prevent issues

You’re responsible for submitting payroll data through Real Time Information (RTI). This includes earnings, tax deductions, and applying the correct tax codes.

If you submit RTI late or it's incorrect, it can contribute to tax calculation issues.

Use the tax codes HMRC provide promptly, and reporting your payroll data on time to help avoid issues.

How to support employees

If an employee receives a P800, they sometimes come to their employer with questions.

While the letter is between them and HMRC, you can help by directing them to their Personal Tax Account on GOV.UK.

They can also use the HMRC app to check their tax code and income. Provide payslips or summaries to help them understand what you've reported.

When a refund is due

If the P800 shows a refund, HMRC explains how the employee can claim it.

Most employees can make online claims using the reference number in the letter.

When tax is owed

If the employee has underpaid tax, HMRC usually adjusts their tax code for the next year.

This spreads the repayment across future pay periods. Sometimes, HMRC can ask the employee to pay the amount directly.

To find out more about form P800, go to HMRC's employee guidance at GOV.UK.