The HMRC P800 Letter: What It Means and How to Claim Your Tax Refund

Each year between June and November, HMRC automatically reviews the tax paid by millions of individuals under the Pay As You Earn (PAYE) system. If this reconciliation process reveals that you have paid the wrong amount of income tax over the preceding tax year, HMRC will issue a formal document called a “P800 tax calculation” letter. Understanding what the P800 letter is, how to interpret its figures, and the exact steps required to claim your refund is essential. This guide outlines the official HMRC processes and timelines for the 2026/27 tax year.

Why Did I Receive a P800 Tax Calculation?

The PAYE system is designed to collect tax incrementally throughout the year based on your tax code. However, it is not always 100% accurate. HMRC triggers a P800 calculation if they determine that your actual income tax liability for the year does not match the total tax deducted by your employer or pension provider. Common reasons for receiving a P800 letter include:

• Changing Jobs: If you moved between employers and had a period where an emergency tax code was applied or your tax-free allowance was not properly distributed.
• Variable Earnings: If you received large, irregular bonuses or commissions that distorted your monthly PAYE calculations.
• Multiple Income Streams: Earning taxable income from more than one job or pension simultaneously without split tax codes.
• State Benefits or Pension Changes: Commencing or ending state benefits, or starting to draw a private pension mid-year.

Official HMRC P800 Refund Timelines

For the tax year that ended on 5 April 2026, HMRC begins running its automated reconciliations and mailing P800 letters starting in **June 2026**. The bulk of these notifications are distributed throughout the summer, concluding by **November 2026**. If you are due a refund, the letter will specify the amount overpaid and explain whether you can claim online or if a paper cheque will be sent automatically. If you do not receive a letter by December but believe you overpaid, you should log into your Personal Tax Account (PTA) or call HMRC.

How to Claim Your Refund Safely

If your P800 letter states you can claim online, log into the official government gateway or use the HMRC app. Do not click on links in text messages or emails claiming to be from HMRC; these are common phishing scams. The government will never send a text message with a direct link to claim a tax refund. Once logged in, you will be prompted to enter your bank account number and sort code. HMRC will process the payment directly to your account. If you do not claim online within 21 days, HMRC will automatically mail a paper cheque to the address they have on file for you.

To verify if your tax calculations align with HMRC’s records, use our online Tax Refund Calculator.

Frequently Asked Questions: HMRC P800 Letter

1. What is an HMRC P800 letter?
A P800 is an official tax calculation letter sent by HMRC if they find you paid the wrong amount of tax via PAYE over the tax year. It details whether you are owed a tax refund or if you owe HMRC underpaid tax.

2. When does HMRC send out P800 letters for 2026?
HMRC distributes P800 tax calculation letters between June and November each year after the tax year ends. For the 2025/26 tax year, mailing begins in June 2026 and finishes by the end of November 2026.

3. How long does a P800 tax refund take to clear?
Online claims made via your Personal Tax Account are paid directly into your bank account within 3 to 5 working days. If you receive a paper cheque, it typically takes up to 14 days to arrive by post.

4. What should I do if I get a P800 saying I owe tax?
If the P800 states you underpaid tax, HMRC will usually collect the balance automatically by adjusting your tax code for the next tax year, provided you earn enough. If you cannot pay via your tax code, HMRC will write to you with options to pay online or set up a payment plan.

5. Can I check my P800 calculation online?
Yes, you can view, download, and check the details of your P800 calculation by logging into your official HMRC Personal Tax Account. This allows you to verify that the income and tax deduction figures match your final P60 or P45 documents.

6. Why did I not receive a P800 letter?
HMRC only sends a P800 if there is a discrepancy in your PAYE records; if your tax deductions were perfectly correct, no calculation letter is generated. You also will not receive one if you are registered for Self Assessment, as your reconciliation happens via your tax return.

7. How do I know if a P800 letter or text is a scam?
Real P800 letters are sent by post and do not contain links to claim websites; HMRC will never text or email you with a direct link to claim a tax refund. Always log in directly through the official gov.uk portal to check your tax status.

8. What is the difference between a P60 and a P800?
A P60 is a summary of your pay and deductions issued by your employer at the end of the tax year, while a P800 is a calculation issued by HMRC summarizing your overall tax position across all employers. Your P800 uses the data from your P60 to check for errors.

9. How far back can HMRC check for underpaid or overpaid tax?
HMRC can issue P800 calculations or tax assessments backdated for up to 4 tax years. For the 2026/27 tax year, you can claim refunds or be assessed for tax overpayments dating back to the 2022/23 tax year.

10. Does a P800 refund include interest?
If your refund is delayed, HMRC may pay a “repayment supplement,” which is interest calculated on the tax overpayment from the date of the overpayment to the refund date. The interest rate is tied to the Bank of England base rate.