4 articles tagged with P800.
If HMRC owes you a tax refund, you may need to use R38, R40, P800 or R43. Learn which form applies to your situation and how to reclaim overpaid tax in 2026/27.
An HMRC P800 (Tax Calculation) letter tells you if you've overpaid or underpaid tax. If you're owed a refund, you can claim it online within 45 days. If you owe tax and it's under £3,000, HMRC usually collects it through your next year's PAYE tax code.
Received an HMRC P800 or Simple Assessment letter about underpaid tax? Learn why it happens, how to check it, challenge it, and the ways HMRC collects the debt.
What happens after you submit your UK self assessment return: how to get a refund, how to correct mistakes, what to do if HMRC opens an inquiry, and your rights.
