I received a P800 letter - what do I do?
A P800 is an annual tax calculation sent by HMRC to PAYE taxpayers who have either overpaid or underpaid income tax. It is not a penalty or demand - it is simply HMRC reconciling your tax account at the end of the year. Here is exactly what to do.
What is a P800?
HMRC sends P800 letters between June and November each year, after the tax year ends on 5 April. They compare the income tax your employer(s) deducted through PAYE against what HMRC calculates you should have paid, based on all your income sources.
The letter will say one of two things:
- You have paid too much tax - HMRC owes you a refund. This is the most common outcome and is what most people mean when they talk about a P800.
- You have paid too little tax - You owe HMRC money. HMRC usually collects this by adjusting your tax code for the following year (rather than demanding a payment upfront), unless the amount is over £3,000.
When you are owed a refund: your options
Option 1: Claim online (recommended)
The letter will contain a unique claim reference and a web address. Go online, sign in with your Government Gateway account or GOV.UK One Login, and confirm your bank details. HMRC will pay the refund directly into your bank account within 5 working days.
Fastest option - money in your account within a week.
Option 2: Do nothing - receive a cheque
If you do not claim online within 45 days, HMRC automatically sends a payable order (cheque) to your registered address. This takes up to 5 weeks after the 45-day window. The cheque must be paid in within 6 months.
Slower, but requires no action from you.
When you owe tax: what happens
If the P800 shows you owe tax, HMRC will usually collect it via an adjusted tax code in the following year - spreading the collection across 12 months. For example, if you owe £400, HMRC reduces your tax-free allowance by £2,000 (since 20% of £2,000 = £400), and your next year's code will be something like 1057L instead of 1257L.
You can also choose to pay immediately via your Personal Tax Account, which prevents any adjustment to next year's code.
If you owe more than £3,000, HMRC cannot collect it via a code adjustment alone and will contact you separately about payment.
What if you think the P800 is wrong?
P800 calculations can contain errors. Common sources of mistakes include:
- Income from a previous employer not included correctly
- Pension contributions not taken into account
- Benefits in kind (company car, health insurance) valued incorrectly
- State benefits (Jobseeker's Allowance, Employment and Support Allowance) included at the wrong amount
- Savings interest included when it falls within your Personal Savings Allowance
If you disagree with the calculation, do not simply accept the refund if you believe it should be higher. Contact HMRC on 0300 200 3300 with your P60(s), payslips and the P800 letter to hand, and ask them to review the calculation. You can also write to HMRC at the address on the letter.
P800 checklist
Check the letter is genuine - look up the HMRC telephone number independently, not from the letter, to verify
Compare the income figures on the P800 against your P60(s) - they should match
Check pension contributions are reflected if you use relief at source
Verify any benefit-in-kind amounts against your P11D
If claiming online, use your actual Government Gateway credentials - not a link from an unexpected email
Note the claim deadline date printed on the letter
Keep a copy of the P800 letter and confirmation of your claim
Beware of P800 scams
HMRC never sends tax refund notifications by email or text message. If you receive an unsolicited email or SMS claiming to be from HMRC offering a refund, it is a phishing scam. Do not click any links. Forward suspicious emails to phishing@hmrc.gov.uk and delete them. Always go directly to gov.uk to check your tax position.
What if you do not receive a P800?
Not everyone who overpaid tax gets a P800. HMRC only sends them when its own records clearly show a discrepancy. If you believe you overpaid but have not received a letter, you can still claim directly through your Personal Tax Account under "Check your tax for a previous year."
You can claim for up to four previous tax years. So if you have never checked, it is worth reviewing each year going back to 2021/22.
Verify the amount with our calculator
Enter your annual salary and tax code to see what you should have paid. Compare to your P60 total - any difference is likely refundable.
Open salary calculator