Each year, HMRC issues around 3 million P800 letters to UK taxpayers, with the average refund amounting to approximately £750. Despite being one of the most common documents in the UK tax system, many people who receive one are unsure what it means, whether to act on it, or how to avoid losing the money they are owed. This guide explains everything you need to know about the P800 tax calculation, including how to claim your refund, what to do if you have underpaid, and how to protect yourself from scams.

What Is a P800 Form?

A P800 is an official tax calculation letter sent by HM Revenue & Customs (HMRC). It is not a form you fill in it is a notice issued to you, usually by post or through your HMRC online account, after HMRC has completed its end-of-year review of your Pay As You Earn (PAYE) records.

The P800 compares how much Income Tax you actually paid during the tax year as deducted from your salary or pension by your employer or pension provider with how much HMRC calculates you should have paid based on your total taxable income and allowances. If there is a discrepancy, HMRC will inform you of the difference via a P800.

The official name used on gov.uk is the tax calculation letter, though it is widely known as the P800 in accountancy and tax circles. The form relates to Income Tax only and is exclusively for individuals taxed through PAYE. It does not relate to National Insurance Contributions or Capital Gains Tax.

What Does a P800 Show?

A P800 tax calculation letter contains the following information:

• Your total gross income recorded by HMRC for the relevant tax year (including all employment income, pensions, and state benefits if applicable)
• Your tax-free Personal Allowance for that year (£12,570 for 2025/26)
• Any taxable benefits in kind reported by your employer on form P11D
• Any work expenses or tax reliefs already claimed
• The total Income Tax you paid during the year through PAYE
• HMRC’s calculation of how much tax you should have paid
• The difference — either the amount HMRC owes you (overpayment) or the amount you owe HMRC (underpayment)

Why Have I Received a P800? Common Reasons for Tax Overpayment

HMRC issues a P800 only when your tax position for the year is not correct. This can happen for a number of reasons, most of which are entirely routine and not the result of any error on your part.

Reason	Explanation
Emergency tax code applied	When you start a new job without a P45, your employer may place you on an emergency tax code (e.g. 1257L W1/M1 or 0T), which often results in overtaxation until HMRC corrects the code.
Multiple employments or pensions	If you worked for more than one employer simultaneously, or received both a salary and a pension, tax may have been deducted twice on income that should have benefited from the personal allowance only once.
Leaving employment mid-year	If you stopped working before the end of the tax year and did not transfer your code to a new employer, you may have paid more tax than was due on a lower annual income.
Unclaimed work expenses	If you were entitled to tax relief on work-related expenses (e.g. uniforms, professional subscriptions, tools) but did not claim in-year, HMRC may recognise the overpayment at year-end.
Income lower than forecast	If your income dropped during the year, your employer may have continued deducting tax based on an earlier, higher estimate.
Tax code changes applied late	If HMRC updated your tax code mid-year, the correction may have come too late to prevent overpayment in earlier months.
State benefits received	Some state benefits (e.g. Jobseeker’s Allowance or carer payments) are taxable and can affect the tax calculation in ways that create discrepancies.

How to Claim a P800 Tax Refund Online: Step-by-Step

Important update for 2026: From 31 May 2024, HMRC stopped issuing all repayments automatically. If your P800 says you can claim online, you must actively log in and submit your claim. HMRC will not automatically send a cheque in most cases unless your letter specifically states it will.

Method 1: Claim Online via gov.uk/p800refund (Fastest)

This is the fastest method and typically results in payment reaching your bank account within 5 working days.

1. Locate the 10-digit P800 reference number at the top of your HMRC letter.
2. Visit gov.uk/p800refund in your browser. Confirm the address ends in .gov.uk and shows a padlock icon before entering any personal information.
3. Select ‘Claim now’ and sign in using your Government Gateway user ID and password, or create a new account if you do not already have one.
4. Enter your National Insurance number and confirm that your total income for the year matches the figure on your letter.
5. Provide the sort code and account number for a UK bank account in your own name. HMRC will not transfer to a third-party account without written authorisation.
6. Review the summary and submit your claim.
7. Save the confirmation reference number provided at the end of the process.

Method 2: Claim via the HMRC App

You can also claim through the official HMRC app, available on iOS and Android. Log in using your Government Gateway credentials, navigate to your Personal Tax Account, and follow the prompts to claim your refund. The timescale is the same as the online method — typically 5 working days.

Method 3: Receive a Cheque Automatically

In some circumstances, HMRC will state in your P800 letter that a cheque will be sent to you automatically without you needing to take action. In this case, the cheque should arrive within 14 days of the date on your letter. If you have been owed tax from more than one year, HMRC will issue a single cheque for the combined amount.

Method 4: Contact HMRC by Phone

If you are unable to claim online or via the app, you can call the HMRC Income Tax helpline on 0300 200 3300 (Monday to Friday, 8am to 6pm) to request your refund by cheque. Be prepared to confirm your identity with your National Insurance number and personal details.

P800 Refund Timescales at a Glance

Claim Method	Timescale	Payment Method
Online (gov.uk/p800refund)	5 working days	Bank transfer
HMRC app	5 working days	Bank transfer
Automatic cheque (HMRC sends)	Within 14 days of letter date	Cheque by post
Phone request (cheque)	Up to 6 weeks	Cheque by post
HMRC processing backlog periods	May be longer	Bank transfer or cheque

What Should I Do If My P800 Shows I Have Underpaid Tax?

Receiving a P800 that shows an underpayment can be concerning, but HMRC handles these situations in a straightforward and proportionate way. You will not face penalties simply because you underpaid through PAYE that is not your fault; it is the result of your employer or pension provider deducting the wrong amount, or your circumstances changing during the year.

How HMRC Collects Underpaid Tax

Statute of limitations: HMRC can generally only collect underpaid PAYE tax going back four tax years. Underpayments arising from HMRC’s own error may be subject to the ESC A19 concession, which can allow certain older underpayments to be written off where the taxpayer could not reasonably have known about them.

How Far Back Can You Claim a P800 Refund? The 4-Year Rule

HMRC allows you to claim overpaid tax for up to four complete tax years before the current one. Each tax year runs from 6 April to 5 April. Below are the current claim deadlines:

Tax Year	Claim Deadline	Status
2021/22 (6 Apr 2021 – 5 Apr 2022)	5 April 2026	Deadline approaching claim now
2022/23 (6 Apr 2022 – 5 Apr 2023)	5 April 2027	Open
2023/24 (6 Apr 2023 – 5 Apr 2024)	5 April 2028	Open
2024/25 (6 Apr 2024 – 5 Apr 2025)	5 April 2029	Open

If you have not received a P800 but believe you are owed a refund: Log in to your HMRC Personal Tax Account and check your Income Tax summary, or write to HMRC clearly marked ‘Repayment Claim’ including your National Insurance number, personal details, and relevant P60s or P45s as supporting evidence.

What Should I Do If My P800 Is Wrong?

If the figures on your P800 do not match your payslips, P60, or other income records, it is important to query this with HMRC promptly. The most common reasons for an incorrect P800 are:

• An employer or pension provider submitted incorrect figures to HMRC
• A benefit-in-kind (reported on P11D) has been included or omitted incorrectly
• A tax relief or allowance you are entitled to has not been applied
• Income from a previous year has been included in the wrong period

How to dispute a P800: 

1. Gather your payslips, P60, P45, and any P11D from your employer for the relevant year.
2. Compare each figure with what appears on the P800.
3. If you identify a discrepancy, contact HMRC on 0300 200 3300 or write to HMRC with your evidence.
4. Do not ignore a P800 showing an underpayment if you believe it is wrong. Ignoring it does not make it go away — HMRC will still attempt to collect via your tax code.

Tip: Check Your Tax Code First Many P800 discrepancies arise from incorrect tax codes. You can view and verify your current and historic tax codes in your HMRC Personal Tax Account. If your code was wrong during the year, this could explain why you overpaid or underpaid. Common problem codes include emergency codes (e.g. 1257L W1/M1), which treat you as if you have no previous pay or tax in the year, and BR (Basic Rate on all income), which applies 20% tax to all income with no personal allowance.

P800 vs P60: What Is the Difference?

These are two of the most common HMRC documents that UK employees encounter, and they are frequently confused. Here is a clear comparison:

Feature	P800	P60
Issued by	HMRC	Your employer or pension provider
Purpose	Shows if you overpaid or underpaid tax	Confirms your total pay and tax for the year
When issued	June to November (after year end)	By 31 May (after year end)
Contains	Tax calculation comparing expected vs actual tax paid	Gross pay, total Income Tax, NIC deducted
Action required	Yes — claim refund or pay shortfall	Keep as a record; use to check P800 figures
Can you request it?	No — HMRC issues automatically if needed	From your employer if not received by 31 May
Used for what?	Triggering a refund or collection	Proof of income (e.g. mortgage, benefits)

How to Spot a P800 Scam: Protecting Yourself from Fake HMRC Refund Messages

In the 12 months leading to January 2024, HMRC received over 200,000 scam reports a 29% rise on the previous year. In late 2024 and into 2026, scammers have become increasingly sophisticated, using AI deepfake technology and spoofed SMS messages to mimic genuine HMRC communications. Fake P800 refund messages are one of the most common formats used.

HMRC Will NEVER Do Any of the Following: • Send a P800 refund notification by text message, WhatsApp, or email with a link to claim. • Ask for your bank details, card numbers, PIN, or passwords via text or email. • Demand immediate payment by gift card, cryptocurrency, or bank transfer to a private account. • Threaten arrest, legal action, or bailiffs without prior official written correspondence. • Send a refund to a third-party bank account on your behalf without written authorisation from you.

How to Verify a Genuine P800

Can Self-Employed People Receive a P800?

No. The P800 is issued exclusively to individuals who are taxed through PAYE — that is, employees and pensioners whose tax is deducted at source by an employer or pension provider. Self-employed individuals, sole traders, and those with complex income do not receive a P800.

If you are self-employed and believe you have overpaid tax, you claim any refund through your Self Assessment tax return. When you submit your return, HMRC automatically calculates whether a repayment is due and will either:

• Transfer the refund to your bank account (if you provide details on the return), or
• Offer the option to offset the overpayment against next year’s tax bill

Note: If you receive PAYE income in addition to self-employment income, HMRC may still issue a P800 in relation to your PAYE income. However, any self-employment tax position will be reconciled through Self Assessment separately.

I Have Not Received a P800 — Can I Still Claim a Tax Refund?

Yes. Not receiving a P800 does not mean you are not owed a refund. HMRC only issues a P800 when its systems detect a discrepancy — and the system is not infallible. If you believe you may have overpaid tax but have not received a P800, there are several routes available:

Can I Receive More Than One P800?

Yes. If HMRC conducts end-of-year checks across more than one tax year simultaneously, you may receive multiple P800 letters, each relating to a different year. Each letter will show the position for that specific tax year independently. If you receive a refund from multiple years, HMRC will usually issue a single combined cheque rather than separate payments.

Frequently Asked Questions: P800 Tax Refund

What is a P800 form in the UK?

A P800 is a tax calculation letter issued by HMRC to PAYE employees and pensioners after the end of the tax year. It shows whether you have paid the correct amount of Income Tax, too much, or too little. If you overpaid, it tells you how to claim a refund. If you underpaid, it explains how HMRC intends to collect the shortfall, usually through your tax code.

How do I claim my P800 refund online?

Visit gov.uk/p800refund and click ‘Claim now’. Sign in with your Government Gateway credentials. You will need the 10-digit reference number from the top of your P800 letter, your National Insurance number, and your UK bank account details (sort code and account number). Refunds are usually paid within 5 working days.

How long does a P800 refund take?

Online claims via gov.uk or the HMRC app typically take 5 working days to reach your bank account. If HMRC sends you a cheque automatically (stated in your letter), it should arrive within 14 days of the letter date. Requesting a cheque by phone can take up to 6 weeks.

What if my P800 shows I underpaid tax?

If your P800 shows an underpayment, HMRC will usually collect it by adjusting your tax code in the next tax year, spreading the cost over 12 months. For amounts over £3,000, or if you would prefer to pay in full, contact HMRC on 0300 200 3300. You can also arrange a Time to Pay plan if paying immediately is not possible.

What is the difference between a P800 and a P60?

A P60 is issued by your employer by 31 May each year and shows your total pay and Income Tax deducted during that tax year. A P800 is issued by HMRC and compares the tax recorded in your P60 and employer submissions against HMRC’s own calculation of what you should have paid. Think of the P800 as HMRC’s audit of your P60 figures.

Can self-employed people get a P800?

No. A P800 is only issued to PAYE employees and pensioners. If you are self-employed, you reconcile your tax position through your Self Assessment tax return, which HMRC uses to calculate whether any refund is due. Self-employed refunds are processed automatically after submission.

How far back can I claim a P800 refund?

You can claim overpaid tax for up to four tax years prior to the current year. As of March 2026, you can claim back to 2021/22, but the deadline for that year is 5 April 2026. Claims for 2022/23, 2023/24, and 2024/25 remain open with deadlines in subsequent years.

What should I do if I think my P800 is incorrect?

Compare the figures on your P800 with your P60, payslips, and any P11D forms from your employer. If you identify a discrepancy, contact HMRC on 0300 200 3300 or write to HMRC with documentary evidence. Do not ignore a P800 showing an underpayment even if you believe it is wrong — challenge it proactively to avoid automatic tax code adjustments.

Is a P800 refund genuine if received by text or email?

No. A genuine P800 will only appear in your HMRC Personal Tax Account online or arrive by post to your registered address. HMRC does not contact taxpayers about P800 refunds by text, email, WhatsApp, or social media. Any such message is a scam. Forward suspicious emails to phishing@hmrc.gov.uk and report suspicious texts to 7726.

What happens if I don’t claim my P800 refund?

From 31 May 2024, HMRC stopped automatically sending cheques for most P800 refunds. If your P800 says you can claim online, you must actively claim it. If you do not claim, the refund remains on your tax record, but you will eventually reach the 4-year deadline after which the right to claim expires. Claim as soon as possible to avoid losing money that is rightfully yours.