Example of a P800 Tax Calculation
Let’s look at a straightforward example of how a P800 calculation might work.
Sarah works for a UK business and earns £35,000 during the 2025/26 tax year. She lives in England, receives the standard Personal Allowance and has no other taxable income or relevant adjustments.
| Description | Amount |
|---|
| Total annual salary | £35,000 |
| Personal Allowance | £12,570 |
| Taxable income | £22,430 |
| Income Tax due at 20% | £4,486 |
| Income Tax already deducted | £4,750 |
| Income Tax overpaid | £264 |
In this example, Sarah has paid £264 more in Income Tax than she should have.
HMRC could therefore issue a P800 confirming that she’s entitled to a £264 refund.
The same calculation works in reverse. If Sarah had only paid £4,200 in Income Tax, she would have an underpayment of £286.
Real P800 calculations may include additional adjustments, particularly where an individual has multiple income sources, taxable benefits or changes to their tax allowances.
Why Would HMRC Send You a P800?
There are several reasons why the Income Tax deducted during the year might not match your final liability.
You’ve Changed Jobs
Changing employers can sometimes cause temporary issues with PAYE tax calculations.
For example, your new employer might initially use an emergency tax code because it hasn’t received your previous employment details.
Once HMRC reconciles the figures, it may discover you’ve paid too much or too little tax.
You’ve Had More Than One Job
If you work for multiple employers, your Personal Allowance needs to be allocated correctly.
A second job is often taxed using a code such as BR or D0, which taxes all pay at a flat rate with no allowance.
If the allowance has been applied incorrectly across your employments, your total tax deductions might not reflect your actual liability.
Your Tax Code Was Incorrect
Your tax code tells your employer how much tax-free income to take into account when calculating PAYE deductions.
An incorrect code can result in too much or too little tax being deducted.
You can learn more in HMRC’s guide to tax codes.
You’ve Received Taxable Benefits
Company cars, private medical insurance and certain other employment benefits can increase your taxable income. Our guide to benefit in kind and company cars explains how these are taxed.
If these benefits weren’t reflected correctly in your tax code or payroll deductions, HMRC may need to adjust your final tax calculation.
You’ve Started Receiving a Pension
Receiving pension income alongside employment earnings can affect your tax position.
The State Pension is also taxable, although tax is not normally deducted directly from State Pension payments.
HMRC may account for this through adjustments to your tax code or a year-end calculation.
You’ve Stopped Working Partway Through the Year
If you leave employment and don’t work again during the same tax year, you may have paid more tax than necessary.
This can happen because PAYE deductions were originally calculated on the assumption that your employment income would continue.
What Does a P800 Tax Refund Mean?
If your P800 shows that you’ve overpaid Income Tax, HMRC will explain how the refund can be claimed or paid.
Depending on your circumstances, you may be able to claim your refund online or receive a cheque.
HMRC may also issue a refund automatically in some cases.
How to Claim a P800 Tax Refund
If HMRC asks you to claim online, you’ll normally need to follow the instructions provided in your P800 notification.
The process generally involves:
- Checking that the P800 is genuine and the calculation is correct.
- Visiting the official GOV.UK service using the instructions provided.
- Confirming your identity where required, which usually means signing in with your Government Gateway ID.
- Providing the requested details to claim your refund.
- Waiting for HMRC to process the payment.
HMRC states that online P800 refund claims are normally paid within five working days, although individual circumstances can affect processing times.
If a refund is issued by cheque, it will generally take longer to arrive.
For more information, visit GOV.UK’s guidance on claiming an Income Tax refund.
How Long Do You Have to Claim a P800 Refund?
Income Tax overpayment claims are generally subject to a four-year time limit from the end of the relevant tax year.
For example, a claim relating to the 2022/23 tax year would generally need to be made by 5 April 2027.
However, the exact process and deadline can depend on the type of claim and how HMRC has notified you.
It’s always worth checking the instructions on your P800 rather than leaving a refund unclaimed.
What Happens If Your P800 Says You Owe Tax?
Receiving a P800 showing an underpayment can be frustrating, especially if you assumed your employer had deducted the correct amount throughout the year.
However, PAYE deductions are based on the information and tax code available at the time. Your final tax liability can change once HMRC has reviewed your full-year income.
If you owe tax, HMRC will explain how it intends to collect the outstanding amount.
Collection Through Your Tax Code
For eligible underpayments, HMRC may collect the outstanding tax by adjusting your PAYE tax code for a future tax year.
This spreads the collection through your wages or pension rather than requiring one immediate payment.
HMRC can normally collect eligible PAYE underpayments of less than £3,000 through a tax code, provided the relevant conditions are met.
There are also limits designed to prevent excessive deductions from your income.
Paying HMRC Directly
If HMRC cannot collect the underpayment through your tax code, it may ask you to pay directly.
Your notification should explain the payment options and any applicable deadline.
If you’re unable to pay the full amount, contact HMRC promptly to discuss your circumstances and whether a payment arrangement is available.
Further guidance is available at GOV.UK: If you owe tax.
Can HMRC Charge Penalties or Interest on a P800?
Receiving a P800 does not automatically mean you’ll face a penalty.
A P800 simply identifies a difference between the tax HMRC believes you owe and the tax already paid.
For routine PAYE underpayments, HMRC will normally explain how the outstanding tax is to be collected.
However, interest or penalties may arise in other circumstances, such as where a separate tax assessment becomes overdue or a taxpayer has failed to meet a legal obligation.
If you believe an underpayment resulted from an error by HMRC, you may also want to consider whether Extra-Statutory Concession A19 applies.
This concession can, in certain circumstances, allow HMRC to give up collecting tax where it failed to make proper and timely use of information it had received and the taxpayer reasonably believed their tax affairs were in order.
It isn’t automatic, and specific conditions must be satisfied.
See HMRC’s guidance on Extra-Statutory Concession A19.
What Should You Do If Your P800 Is Wrong?
HMRC doesn’t always have a complete or accurate picture of your financial circumstances.
If the information used in your P800 is incorrect, the resulting tax calculation could also be wrong.
Before accepting the figures, it’s worth carrying out a few checks.
1. Check Your Employment Income
Compare the income shown on your P800 with your P60, P45 and final payslips for the relevant tax year.
If you’ve changed jobs, make sure HMRC hasn’t duplicated income or missed an employment.
2. Check Your Tax Deductions
Review the Income Tax deducted by each employer or pension provider.
These figures should broadly reconcile with your PAYE records, taking account of any adjustments or refunds already made.
3. Review Your Allowances and Reliefs
Check whether your Personal Allowance and any other applicable reliefs have been calculated correctly.
For example, an incorrect Marriage Allowance adjustment or missing employment expense relief could affect the final figure.
4. Check Any Taxable Benefits
If you’ve received company benefits, compare HMRC’s figures with the information reported by your employer.
This may include your P11D or details of benefits taxed through payroll.
5. Contact HMRC About Any Discrepancies
If you identify a mistake, contact HMRC and explain which figures you believe are incorrect.
Keep supporting documents available, including payslips, P60s, P45s and relevant correspondence.
You can find the appropriate contact details through HMRC’s official contact page.
Don’t simply ignore an incorrect P800, particularly if it shows an underpayment. Resolving the discrepancy early can help prevent further complications.
What Does a P800 Mean for Limited Company Directors?
If you’re a limited company director, you might assume that your company’s accountant deals with every aspect of your tax position.
However, your company’s tax obligations and your personal Income Tax obligations are separate.
Directors receiving a salary through PAYE can receive a P800 in much the same way as other employees. If you’re unsure how salary fits into your overall pay, see our guide on how to pay yourself from your business.
For example, you might receive a P800 if:
- You’ve received salary payments from more than one employment.
- Your tax code was incorrect.
- You’ve received taxable benefits through your company.
- Your employment income changed significantly during the year.
- HMRC has updated information affecting your PAYE deductions.
What About Dividends?
Many limited company directors receive a combination of salary and dividends.
Unlike salary, dividends are not normally subject to PAYE deductions.
Dividend income may need to be reported and taxed separately, depending on the amount received and your circumstances. Our step-by-step guide to UK dividend tax explains how this works.
If you complete a Self Assessment tax return, your overall personal tax liability will normally be reconciled through Self Assessment rather than a P800.
This is why it’s important not to assume that a P800 necessarily represents your complete personal tax position.
At Accounting Wise, we provide limited company accounting services that help directors manage company accounts, payroll, Corporation Tax and personal tax obligations, ensuring the different parts of their finances work together properly.
Does a P800 Affect Your Business Accounts?
For business owners and company directors, it’s important to distinguish between personal tax and business tax.
A P800 relates to an individual’s Income Tax position. It doesn’t directly change your company’s Corporation Tax liability, VAT returns or statutory accounts.
For example, if a director receives a personal Income Tax refund following a P800 calculation, that refund is not automatically company income.
Likewise, if a director owes additional personal Income Tax, the company isn’t automatically responsible for paying it.
However, if the discrepancy relates to incorrect payroll reporting or taxable benefits, the business may need to review its PAYE records and make appropriate corrections.
This is particularly relevant for owner-managed businesses where the director is also responsible for payroll administration. Our guide to payroll and PAYE for your limited company covers the basics.
How Can Employers Help Prevent P800 Tax Discrepancies?
Although employers cannot control every aspect of an employee’s personal tax affairs, accurate payroll reporting helps reduce avoidable problems.
Some useful steps include:
- Use the correct tax codes: Apply the latest tax code notices received from HMRC.
- Report payroll accurately: Submit Full Payment Submissions (FPS) through RTI on or before the relevant payday, subject to HMRC’s exceptions.
- Process starters and leavers correctly: Use appropriate P45 information and starter declarations.
- Report taxable benefits: Ensure benefits are reported through the applicable P11D or payrolling arrangements.
- Maintain accurate employee records: Check National Insurance numbers, names and payroll details.
- Investigate payroll discrepancies: Correct errors promptly when identified.
Mandatory payrolling of benefits in kind starts on 6 April 2027, initially for company cars, car fuel, vans, van fuel and employer-provided medical benefits. Most other benefits follow from 6 April 2028, while loans and accommodation remain voluntary. Employers should make sure their payroll processes are ready for the benefits they provide.
If you’re new to running payroll, see our guide on how to set up a PAYE scheme for your UK business. Employers can find further information in HMRC’s PAYE guidance for employers.
When Does HMRC Send Out P800 Letters?
HMRC generally starts issuing P800 calculations after the end of the tax year, once it has received and processed the information needed to reconcile PAYE records.
The UK tax year runs from 6 April to 5 April the following year.
For example, a P800 relating to the 2025/26 tax year may be issued during 2026, after HMRC has completed the relevant checks.
Not everyone receives their calculation at the same time. Some cases take longer, particularly where multiple income sources or additional information need to be reviewed.
HMRC can also issue calculations relating to earlier tax years.
If you’re expecting a refund but haven’t received a P800, you can check your tax information through your HMRC Personal Tax Account. Not set one up yet? Our guide shows you how to set up your personal tax account with HMRC.
How to Check Whether a P800 Letter Is Genuine
Tax refund scams are common, and fraudsters sometimes impersonate HMRC to persuade people to disclose personal information or bank details.
If you receive an unexpected message claiming you’re owed a tax refund, be cautious.
HMRC does not notify taxpayers about P800 refunds through unsolicited emails or text messages containing links to claim the money.
To protect yourself:
- Don’t click suspicious links in emails or text messages.
- Don’t provide banking details through an unexpected message.
- Access GOV.UK directly rather than following unfamiliar links.
- Check your HMRC Personal Tax Account for relevant information.
- Report suspicious communications using HMRC’s official guidance.
If you’re unsure whether a communication is genuine, visit HMRC’s guidance on scams and suspicious contact.
P800 vs P60 vs Self Assessment: What’s the Difference?
These documents and processes all relate to Income Tax, but they serve different purposes.
| Document or Process | Purpose | Who Uses It? |
|---|
| P800 | Shows whether HMRC believes you’ve overpaid or underpaid Income Tax. | Primarily PAYE taxpayers. |
| P60 | Summarises employment pay and tax deducted during the tax year. | Employees still employed by that employer on 5 April. |
| P45 | Records pay and tax information when employment ends. | Employees leaving a job. |
| Self Assessment | Calculates and reports relevant taxable income, reliefs and tax liability. | Self-employed individuals, landlords, some company directors with income not taxed at source, and others required to file. |
One important distinction is that being a company director doesn’t automatically mean you must submit a Self Assessment tax return. Whether you need to file depends on your income, circumstances and any notice to file issued by HMRC.
Need Help Understanding Your P800 or Personal Tax Position?
Most P800 calculations are straightforward once you understand where the figures come from. However, things can become more complicated when you have multiple employments, taxable benefits, pension income or a combination of salary and dividends.
At Accounting Wise, we help individuals, limited company directors and business owners make sense of their tax obligations.
Whether you need assistance reviewing an unexpected tax calculation, managing your personal tax affairs or ensuring your company’s payroll is being handled correctly, our team can help you understand your position and what needs to happen next.
Need a hand with your tax affairs? Get in touch with Accounting Wise and speak to our friendly team.
Final Thoughts on Understanding Your P800
A P800 is HMRC’s way of checking whether you’ve paid the correct amount of Income Tax during a tax year.
If you’ve overpaid, you may be entitled to a refund. If you’ve underpaid, HMRC will normally explain how the outstanding amount needs to be collected.
The important thing is to check the figures rather than assume they’re automatically correct. Your employment income, tax deductions, allowances and taxable benefits should all match your records.
For company directors and business owners, it’s also worth remembering that a P800 only addresses the relevant personal Income Tax calculation. It doesn’t replace your wider tax reporting obligations.
Keeping accurate records, checking your tax code and dealing with discrepancies promptly can help you avoid unexpected tax bills and make sure you’re not paying more than you should.
