A calculation sent to people outside Self Assessment, reconciling the year. It is only as good as the information HMRC holds — which is frequently estimated rather than actual.
PAYE is designed to collect the right amount of tax across a year, and for someone with one steady job it usually does. Change jobs, hold two, receive savings interest, start a pension, or receive a taxable benefit, and the code driving your deductions can be wrong for part of the year. The P800 is how HMRC squares that up for people who do not file a tax return.
It arrives after the tax year ends, states what HMRC believes your income and tax were, and concludes that you overpaid or underpaid.
What Usually Causes One
- Changing jobs, especially where a P45 was late and an emergency code ran — see P45 explained.
- More than one job or pension at the same time, where allowances were allocated badly between them.
- Starting to draw a pension, particularly a first flexible withdrawal — see emergency tax on pension withdrawals.
- Savings interest above your allowance, reported by banks after the year end — see the Personal Savings Allowance.
- Taxable benefits that were estimated in your code and turned out different.
- Stopping work part-way through the year, which usually produces a refund because allowances are spread evenly across twelve months.
A P800 is a calculation, not a demand or a decision. If the figures are wrong, you say so. HMRC's information comes from employers, pension providers and banks, and where any of them reported something incorrectly the calculation inherits the error.
How to Check It
| Line on the P800 | Check against |
|---|---|
| Employment income | Your P60, or final payslip if you left |
| Pension income | Provider statements |
| Savings interest | Your own totals across every account |
| Benefits in kind | Your P11D |
| Tax paid | P60 and P45 figures added together |
| Allowances given | Whether the right personal allowance was applied |
The line most often wrong is savings interest, because it can be estimated from a previous year rather than taken from actual figures, and because joint accounts are sometimes attributed incorrectly. Interest that has fallen since a high-rate year is a common source of an overstated estimate.
If You Are Owed Money
Refunds are frequently paid automatically to the bank details HMRC holds, or offered through your online account. Where nothing arrives, they can be claimed. The important negative: HMRC will never text or email you a link to claim a refund. Every message of that kind is a scam, and refund season is exactly when they circulate.
If You Owe
- Check the figures first, using the table above.
- Expect it to be collected through your tax code where the amount is modest and you have PAYE income, spreading it over the following year.
- Ask about spreading it if the code adjustment would be unaffordable — see Time to Pay.
- Find out why it happened, because an underlying coding problem left unfixed produces the same result next year.
- Check your current code once the P800 is settled, since collecting an underpayment changes it — see how tax codes work.
Why You Might Not Get One At All
People inside Self Assessment do not receive P800s; their year is reconciled by the return instead. Nor is a P800 issued where HMRC's records show nothing out of line, which can itself be wrong if a source of income was never reported to it. Someone who has had untaxed income for years and never received a P800 should not read that as confirmation the position is correct — see what triggers an enquiry.
Frequently Asked Questions
What is a P800?
An end-of-year tax calculation sent to people outside Self Assessment, reconciling the tax deducted through PAYE against what was actually due. It concludes that you overpaid or underpaid.
Can a P800 be wrong?
Yes, and frequently is. It is built from information reported by employers, pension providers and banks, and savings interest in particular is sometimes estimated from an earlier year rather than actual figures.
How will an underpayment be collected?
Usually through an adjustment to your tax code over the following year, where you have PAYE income and the amount is modest. Larger amounts may be demanded directly, and spreading can be requested.
HMRC texted me about a refund. Is that genuine?
No. HMRC does not send texts or emails with links to claim refunds. Those messages are scams and they circulate most heavily during refund season.
Related Guides
Keep reading with these related guides and calculators:
- How tax codes work — why the code went wrong
- Emergency tax on pensions — a common cause
- Personal Savings Allowance — the line most often wrong
- Time to Pay — if you cannot pay an underpayment
- Check for overpaid tax — claiming a refund
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