HMRC says you are owed something.
Is that the full amount?
A P800 is only as good as the tax code behind it. Check that code free, across every year you can still claim back to 2022/23, and see the total.
What a P800 actually tells you
A P800 is HMRC's end-of-year reconciliation for PAYE taxpayers. After the tax year closes, HMRC compares the tax your employer actually deducted against what its records say you should have paid, and writes to you when the two do not match. Refund letters go out from around June to November. The letter shows the income and allowances HMRC used, the tax due on them, the tax you paid, and the difference.
The part the letter does not show is whether the tax code that produced those deductions was right in the first place. HMRC is reconciling its own figures, using the code it issued. If that code carried the wrong Personal Allowance, a benefit you stopped getting two jobs ago, or an untaxed-income adjustment that no longer applies, the P800 quietly inherits the mistake - and the refund can come out too small just as easily as too large.
Why one year is rarely the whole story
Tax codes are sticky. A wrong code is usually wrong because of something structural - a benefit in kind HMRC never removed, a second job that split your allowance badly, an emergency code that never got corrected - and those things persist across tax years. When a code is wrong in the year HMRC wrote to you about, it is very often wrong in the years either side.
HMRC allows a claim up to 4 years after the end of a tax year. That means 2022/23 is still claimable until 5 April 2027, after which it drops out of reach permanently. The checker above runs all five claimable years at once and totals them, because the total is the number worth acting on, and because the oldest year is the one on a deadline.
No P800? You can still be owed
A P800 is not a guarantee that HMRC has checked everything, and its absence is not evidence that nothing is wrong. HMRC only writes when its automatic reconciliation spots a difference in the records it holds. An error inside the tax code itself - the code being wrong in a way HMRC does not know about - does not trigger a letter. If you file Self Assessment, you will not receive a P800 at all; any overpaid PAYE is settled through your return instead.
Either way, the route to a refund is the same: establish what your code should have been, then take that to HMRC through your Personal Tax Account or on 0300 200 3300. Doing it yourself is free. Refund firms will do it for a percentage - RIFT charges 36% including VAT - of money that was always yours.
How to claim once you know the number
- If you have a P800 showing a refund. Claim it online through the link on the letter or in your Personal Tax Account. HMRC says the money usually lands in about 5 working days; leave it 21 days and a cheque follows within 6 weeks instead.
- If you have no P800, or it looks wrong. Sign in to your Personal Tax Account, check the tax code and the income figures HMRC holds for each year, and correct anything out of date. A corrected code for the current year usually reaches your employer in 2 to 4 weeks.
- For closed years. Write to HMRC or call 0300 200 3300 with the years you are claiming and why. Have your P60s and details of income, benefits and deductions for each year to hand - that is what the claim is assessed on.
Related tools and guides
Frequently asked questions
What is a P800 and when does HMRC send one?
A P800 is HMRC’s end-of-year tax calculation for people taxed through PAYE. It arrives after the tax year ends, usually between June and November, and tells you whether your employer deducted too much or too little tax. It is not a bill or a claim form: it is HMRC’s own reconciliation of the PAYE records it holds for you.
How long does a P800 refund take to arrive?
HMRC says a refund claimed online usually reaches your bank account in about 5 working days. If you do not claim within 21 days of the P800 date, HMRC posts a cheque instead, which it says should arrive within 6 weeks of the date on the letter. If neither has turned up in those windows, contact HMRC on 0300 200 3300.
I have not had a P800. Does that mean I am not owed anything?
No. A P800 only covers what HMRC has reconciled from the PAYE records it holds, and it only goes out when HMRC spots a difference. If your tax code was wrong in a way HMRC has not caught, or you have never been sent a calculation for an earlier year, there can still be money sitting there. People who file Self Assessment do not receive P800s at all: their overpayment is settled through the return. Checking your code year by year is how you find out.
Can a P800 be wrong?
Yes. A P800 is only as good as the information HMRC holds. If your tax code carried a benefit you no longer receive, an out-of-date estimate of a company car or medical cover, or an untaxed-income adjustment that no longer applies, the calculation inherits that error. The refund can be too small as easily as too large. Comparing the code that produced the letter against your real circumstances is the way to sanity-check it.
How far back can I claim a tax refund?
HMRC accepts a claim up to 4 years after the end of the tax year, so 2022/23 has to be claimed by 5 April 2027, and after that the oldest year drops out of reach. This checker runs 2026/27, 2025/26, 2024/25, 2023/24 and 2022/23 in one go and totals the estimated refund, because a code that was wrong in one year is very often wrong in the years either side of it.
If the P800 says I underpaid, what happens?
HMRC normally collects an underpayment by adjusting your tax code for a later year, spreading it across your payslips rather than asking for a lump sum. Larger amounts can be requested directly. An underpayment notice is worth checking just as carefully as a refund: if the tax code behind it was wrong, so is the amount HMRC says you owe.
Is this refund figure official?
No, and it is not meant to be. This is an estimate from the tax code, salary and circumstances you enter, using HMRC’s published rates and bands for each year. It is a way to see whether a P800 looks right and whether other years are worth claiming. The binding figure always comes from HMRC. Use the estimate as the reason to go and check.
Does this cost anything, and do I need an account?
The check is free and needs no account. Refund firms typically take a percentage of whatever they recover - RIFT, for example, charges 36% including VAT - for a claim you can make yourself directly with HMRC for nothing. We optionally ask for your email to send a free guide on reclaiming overpaid tax, and you can skip that step.
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Where these figures come from
Rates from GOV.UK.