What is a P800?
A P800 is a tax calculation HMRC sends after the tax year ends if you paid too much or too little income tax through PAYE.
What a P800 means
HMRC compares the tax deducted through PAYE with the tax you should have paid. If they do not match, it sends a P800, usually between June and the end of November after the tax year. It goes to employees and pensioners who are not in Self Assessment.
Common causes include a wrong tax code, an emergency tax code after starting a job, having two jobs or pensions at once, and changes to benefits such as a company car.
Example
An employee changes jobs in 2025/26 and spends three months on an emergency code. In August 2026 a P800 arrives showing £340 overpaid. She claims it through her personal tax account and the money reaches her bank account within about five working days. Had she not claimed online, HMRC would normally have sent a cheque.
If the P800 shows tax owed, amounts under £3,000 are usually collected by adjusting the following year's tax code rather than as a lump sum.
Why P800s happen
PAYE works well for one steady job, but less well when things change during the year. Starting or leaving a job, two jobs at once, a pension starting, a benefit in kind being added or removed, or claiming tax relief for work expenses can all mean the tax deducted ends up wrong. HMRC reconciles the year once employers have sent their final submissions, which is why P800s arrive months after the tax year ends.
If you are in Self Assessment, you will not normally get a P800, because your tax return does the same job.
Why it matters
Always check a P800 against your P60 and payslips, because HMRC's figures depend on the information it holds. Scam texts and emails often copy P800 wording; check your online account rather than clicking links. Our guide on how to claim a tax refund from HMRC covers the process in full.
Common questions
Log in to your HMRC personal tax account directly rather than through any link. Genuine P800 calculations appear there. HMRC does not send refund notices by text or email, and will never ask for your bank details in a message.
Yes. If you think the figures are wrong, for example because HMRC has the wrong income or benefits, contact HMRC with the details. Check your P60, payslips and any P11D first so you can explain exactly which figures are incorrect.