P800 Tax Refund UK Guide 2026
A P800 is an HMRC letter telling you that you paid too much or too little tax through PAYE. If you are owed a refund, claim it online via your Personal Tax Account — refunds typically arrive within five working days. You have a four-year window to claim. Use the timeline checker below to track your refund status.
Last updated: July 2026
Received a P800 from HMRC? This complete guide explains exactly what the letter means, how to claim your refund in minutes, and what to do if your P800 shows an underpayment instead. Do not lose part of your refund to a tax agent — claim it yourself for free.
P800 Refund Timeline Checker
Check when to expect your P800 and how quickly you can receive your refund.
What Is a P800 Tax Calculation?
A P800 is an official letter from HMRC (His Majesty's Revenue and Customs) that shows your complete tax picture for a finished tax year. HMRC produces P800 calculations after reconciling all the income and tax data they have received from employers, pension providers, banks, and government departments.
The P800 compares:
- The total tax you actually paid through PAYE throughout the year
- The total tax you should have paid based on all your income and allowances
The result is either a refund notice (you paid too much tax) or an underpayment notice (you paid too little tax). The vast majority of P800s — roughly 70% — show a refund.
When Does HMRC Send P800 Letters?
HMRC runs its annual end-of-year reconciliation process after the tax year ends on 5 April, and P800 letters go out in batches — typically between June and the end of November. For the 2025/26 tax year, which ended on 5 April 2026, P800s are being sent between June and November 2026:
| Tax Year | Year Ended | P800 Sent | Deadline to Claim Refund Online |
|---|---|---|---|
| 2025/26 | 5 April 2026 | June – November 2026 | 45 days after receipt |
| 2024/25 | 5 April 2025 | June – November 2025 (already sent) | Claim via Personal Tax Account |
| 2023/24 | 5 April 2024 | June – November 2024 (already sent) | Claim via Personal Tax Account |
| 2022/23 | 5 April 2023 | June – November 2023 (already sent) | Deadline: 5 April 2027 |
If you have not received a P800 but believe you are owed a refund, you can proactively check via your HMRC Personal Tax Account. HMRC's reconciliation process does not catch every case, and it is worth checking yourself.
What Triggers a P800 Tax Calculation?
You are more likely to receive a P800 if any of the following applied during the tax year:
- Multiple jobs: Having more than one job where your personal allowance was allocated to one employer but both jobs paid you
- Emergency tax code: Starting a new job on a W1/M1 or BR emergency code
- Changing jobs: Moving employers mid-year where your cumulative tax calculation was disrupted
- State Pension increase: An increase to the State Pension pushes your total income slightly higher than your tax code accounted for
- Bank or savings interest: Interest that exceeds your Personal Savings Allowance (£1,000 for basic rate, £500 for higher rate taxpayers)
- Leaving work: Stopping work mid-year means you used less of your personal allowance than your code assumed
- Company benefits: A car, fuel, or health benefit that was over- or under-estimated
- Pension income: Starting to receive a pension without an accurate tax code being applied from day one
P800 Refund: How to Claim Your Money
If your P800 shows you are owed a refund, here is exactly what to do:
Check the P800 Letter
Read the letter carefully. Confirm the refund amount and the tax year it relates to. Check that the income figures shown match your payslips and P60. If anything looks wrong, call HMRC before claiming.
Claim Online (Fastest Method)
Visit gov.uk/claim-tax-refund or log in to your HMRC Personal Tax Account. Click “Claim a refund” and follow the instructions. You will need your bank sort code and account number. HMRC pays the refund within 5 working days directly to your bank account.
Wait for Cheque (Slower Method)
If you do not claim online within 45 days, HMRC automatically sends a cheque to your last known address. The cheque takes approximately 21 days to arrive. Make sure your address is up to date on your Personal Tax Account.
Cash or Deposit the Cheque
HMRC cheques are valid for 6 months from the date printed on them. Cash or deposit it promptly. If it expires, contact HMRC to request a replacement.
P800 Underpayment: When You Owe HMRC
If your P800 shows an underpayment (you paid too little tax), do not panic. HMRC rarely demands immediate payment for underpayments identified via a P800. Instead, they use a graduated collection approach:
Underpayments Under £3,000
HMRC adjusts your PAYE tax code for the following tax year to collect the underpayment gradually. For example, if you owe £600, your code number may be reduced by 60 (reducing your tax-free income by £600), resulting in approximately £120 more tax per month over 5 months, or spread over the whole year.
Underpayments Between £3,000 and £30,000
HMRC may ask you to pay directly, either in a lump sum or via self-assessment. If you cannot afford to pay, contact HMRC immediately to set up a Time to Pay arrangement — they are generally flexible.
Underpayments Over £30,000
For significant underpayments, HMRC will likely open a formal investigation or require payment via self-assessment. Professional tax advice is recommended at this level.
If You Disagree with the Underpayment
You have 60 days from the date of the P800 to dispute it. Call HMRC on 0300 200 3300 or respond in writing. Common reasons for incorrect underpayment notices include: pension lump sum taxed at source already, Gift Aid donations not accounted for, or income figures that include non-taxable amounts.
Checking if You're Owed a Refund Without a P800
HMRC does not always send a P800 even when you have overpaid tax. The system is not infallible. Here is how to proactively check whether you are owed money:
- HMRC Personal Tax Account: Log in at gov.uk/personal-tax-account to see your tax history, current year estimates, and whether any refunds are flagged.
- Review your P60: Compare the total tax paid on your P60 with what you should have paid based on your income and allowances. Use our Income Tax Calculator to check.
- Check previous years: You can claim for up to 4 previous tax years. Use HMRC's “Check if you paid the right tax” tool online.
- Contact HMRC: If you suspect you are owed a refund and cannot find it online, call 0300 200 3300 and request a review for specific tax years.
Common scenarios where people are owed refunds but never receive a P800 include: people who were on emergency tax codes for only part of a year, employees who received redundancy pay part of which was taxable, and people who made significant pension contributions that reduced their taxable income.
The 4-Year Time Limit for Claiming Refunds
HMRC imposes a strict 4-year time limit on income tax refund claims. After this deadline, the right to claim lapses permanently and HMRC will not make exceptions.
In the current 2026/27 tax year (6 April 2026 to 5 April 2027), the years you can still claim for are:
| Tax Year | Claim Deadline | Status |
|---|---|---|
| 2022/23 | 5 April 2027 | Expires this tax year |
| 2023/24 | 5 April 2028 | Open |
| 2024/25 | 5 April 2029 | Open |
| 2025/26 | 5 April 2030 | Open |
How P800 Tax Refund UK Guide 2026 Works
P800 letters arriving during 2026 reconcile the 2025/26 tax year, so the figures below are the 2025/26 HMRC rates — and these thresholds are unchanged for the current 2026/27 tax year. The UK uses a progressive tax system where different portions of your income are taxed at different rates. Only income above the tax-free personal allowance is subject to tax, and each band applies only to the slice of income within that range.
Understanding your tax liability helps you make informed decisions about pension contributions, salary sacrifice, gift aid donations, and other tax-efficient strategies. This tool provides an estimate based on standard tax codes, though your actual position may differ if you have multiple income sources or special circumstances.
Key Tax Figures for 2025/26 and 2026/27
The personal allowance is £12,570 (frozen until 2028). Basic rate: 20% on income from £12,571 to £50,270. Higher rate: 40% on income from £50,271 to £125,140. Additional rate: 45% on income above £125,140. The personal allowance reduces by £1 for every £2 earned above £100,000, creating an effective 60% rate between £100,000 and £125,140.
Example Calculation
On £42,000 annual income in 2025/26: £12,570 is tax-free, then £29,430 is taxed at 20% = £5,886 income tax. National Insurance adds £2,354 at 8% on earnings above £12,570. Total deductions: £8,240, leaving take-home pay of £33,760 per year or £2,813 per month.
Source: Based on official HMRC 2025/26 tax rates. Last Updated July 2026.
Frequently Asked Questions
What is a P800 tax calculation?+
A P800 is a letter from HMRC sent after the tax year ends. It shows your total income and tax paid versus what you should have paid, resulting in either a refund or an underpayment notice. It is typically sent between June and the end of November after the tax year ends — so P800s for 2025/26 arrive between June and November 2026.
How do I claim my P800 refund online?+
Log in to your HMRC Personal Tax Account at gov.uk/personal-tax-account. Navigate to 'Check if you paid the right amount of tax' and follow the prompts to claim. You will need your bank details.
HMRC pays the refund within 5 working days. Do not use a third-party tax refund company.
How long does a P800 refund take?+
Claiming online: 5 working days to your bank. Not claiming online: HMRC sends a cheque automatically after 45 days, which takes 21 days to arrive. Total for cheque route: approximately 10 weeks from P800 issue date. Online claiming is much faster and more reliable.
What triggers a P800 tax calculation?+
Common triggers include multiple jobs, emergency tax codes, stopping work mid-year, State Pension increases, savings interest exceeding your allowance, company benefits changes, and changing employers. Any event that causes a mismatch between your tax code and actual income can trigger a P800.
Should I use a tax refund company?+
No. Tax refund companies charge 25-40% of your refund plus VAT for work you can do yourself for free in 5 minutes at gov.uk. Some use assignments of income (power of attorney) that allow them to receive all future refunds.
HMRC has warned consumers about these companies. Always claim directly.
What if my P800 shows an underpayment?+
If you owe less than £3,000, HMRC collects it via your tax code next year, spread over 12 months. Larger amounts may require direct payment. If you disagree with the underpayment, contact HMRC within 60 days with evidence. HMRC offers Time to Pay arrangements if you cannot afford to pay immediately.
How far back can I claim overpaid tax?+
4 years. In 2026/27, you can claim for 2022/23 (deadline 5 April 2027), 2023/24, 2024/25 and 2025/26. The window for 2021/22 closed on 5 April 2026. If you suspect you overpaid in 2022/23, check your Personal Tax Account or call HMRC before 5 April 2027.
Official Sources & References
Data verified against official UK government sources. Last checked July 2026.