HMRC P800 letter explained
A P800 brings a full year of pay, pensions, benefits and tax into one calculation. We separate the result from the working so you can see what HMRC says happened.
What this letter usually means
A P800 is an end-of-year Income Tax calculation. It says HMRC believes you paid too much or too little tax and explains how the difference will be dealt with. It is not, by itself, an accusation.
Choose the bit you need right now
Open one view at a time. This keeps a detailed guide manageable when you only need one answer.
Find these six parts
Tax year
The 6 April to 5 April period covered by this calculation.
Income
Pay, pension or other taxable amounts HMRC has included.
Tax paid
Tax HMRC believes was already deducted during the year.
Allowances
Tax-free amounts and reliefs included in the calculation.
Result
The overpayment or underpayment HMRC has calculated.
How it is settled
The letter may describe a refund, a code adjustment or another payment route.
Compare the letter with what you already have
- Is the tax year the one you expected?
- Are all jobs and pensions listed once, with no old source repeated?
- Do the pay and tax-paid figures match P60s, P45s or final payslips?
- Are taxable benefits or other income familiar?
- Does the letter explain how a refund is claimed or an underpayment collected?
Plain-English mini glossary
P800
HMRC’s PAYE tax calculation after the end of a tax year.
Overpayment
The calculation says more tax was paid than HMRC believes was due.
Underpayment
The calculation says less tax was paid than HMRC believes was due.
Taxable income
Income included when HMRC works out Income Tax.
Tax deducted
Income Tax already taken through PAYE.
Coding adjustment
A change to a later tax code intended to collect or return an amount over time.
Useful neutral questions
- Which income source created the difference?
- Where did each pay and tax figure come from?
- Has HMRC included a job or pension twice?
- How does the letter say the amount will be refunded or collected?
- What should I send if one of the figures is not right?
These are prompts, not a statement that anything is wrong.
From envelope to clear next conversation
Find the result
Start with whether HMRC says too much or too little tax was paid.
Check each income source
Match pay, pension and tax figures to your records for that year.
Use an official route
Sign in through GOV.UK rather than an unexpected link or phone number.
Follow the letter
Use the method and any date printed on your own P800.
Try the short audio summary
Use the button to hear this page’s quick explanation. If you order, you can also request a personalised audio copy of the explanation made from your own letter.
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Upload a PDF, scan or clear photographs. We identify the main message, explain unfamiliar wording, pull out dates and actions, and organise neutral questions. Request an audio copy if listening is easier.
Clarity Companion explains document wording only. It does not check tax calculations, provide tax, financial or legal advice, contact HMRC, submit an appeal or act as your representative.
P800 · tax calculation FAQs
Is a P800 the same as a tax return?
No. It is a PAYE tax calculation produced by HMRC using information it holds.
Will every refund arrive in the same way?
No. The method can vary. Read the instructions in your own calculation and use GOV.UK to verify how to claim.
What if a pay or pension figure is wrong?
Gather the relevant P60, P45, payslip or pension statement and contact HMRC using an official route. We can make the wording and figures easier to follow first.
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