P60 Tax Overpayment: How to Check if You Have Paid Too Much
Learn how to read your P60, check whether you have overpaid tax, and claim a refund from HMRC. A practical guide to understanding your end-of-year tax certificate.
Your P60 is the single most important document for checking whether you have overpaid tax during the year. Every employer must give you a P60 after the end of each tax year (by 31 May), and it shows exactly how much you earned and how much tax was deducted. If those numbers do not add up, you could be owed a refund.
What Is a P60?
A P60 is an end-of-year certificate that your employer provides after 5 April each year. It summarises your total pay and total tax deducted for the tax year that has just ended. If you were employed on 5 April, you should receive one. If you left the job before 5 April, you would have received a P45 instead.
Your P60 shows:
- Your total taxable pay for the year
- Total tax deducted through PAYE
- Your National Insurance contributions
- Your tax code at the end of the year
- Your employer's PAYE reference
- Your National Insurance number
How to Check for Overpayment Using Your P60
The basic check is straightforward. Take your total taxable pay from the P60 and calculate what the correct tax should be based on the tax bands and your Personal Allowance for that year.
For the 2025/26 tax year, the standard Personal Allowance is 12,570 pounds. The basic rate of tax is 20% on income from 12,571 to 50,270 pounds, and the higher rate is 40% on income from 50,271 to 125,140 pounds.
**Example:** If your P60 shows total pay of 30,000 pounds, the correct tax should be: 30,000 minus 12,570 = 17,430 pounds taxable at 20% = 3,486 pounds. If your P60 shows more than 3,486 pounds in tax deducted, you have overpaid.
Of course, this gets more complicated if you changed jobs, had benefits in kind, or had an adjusted tax code. The easiest way to check is to use a free calculator like AuditMyTax. Upload your P60 and it will instantly compare the tax deducted against the correct amount.
Common Reasons Your P60 Shows an Overpayment
**Wrong tax code.** If HMRC assigned you the wrong tax code at any point during the year, you will have paid the wrong amount of tax. Check the tax code shown on your P60 against what it should have been. The standard code for 2025/26 is 1257L.
**Started a new job mid-year.** If you were not working for part of the year, you should have used some of your Personal Allowance during those months. If your employer's PAYE system did not account for this, you will have overpaid.
**Emergency tax code.** If you see W1 or M1 next to your tax code on payslips, you were on a non-cumulative emergency code. Your P60 might show the correct cumulative code at the end, but you may still have overpaid in the months the emergency code was active.
**Multiple employments.** If you had two jobs, your Personal Allowance should only be applied to one of them. If it was split incorrectly, or if both employers applied it, the end result on your P60s combined might show an over or underpayment.
What If You Have Lost Your P60?
If you have lost your P60, your employer is required to provide details but is not legally obligated to issue a duplicate P60 form. However, most employers will provide one if you ask. You can also find the same information on your final payslip of the tax year, or in your HMRC Personal Tax Account online.
How to Claim a Refund
If your P60 confirms you have overpaid, you have several options:
1. **Check your Personal Tax Account** at gov.uk for a P800 tax calculation. If HMRC has already identified the overpayment, you can claim online and receive the refund within 5 working days.
2. **Call HMRC** on 0300 200 3300. Have your P60, National Insurance number, and employment details ready. Ask for a review of the tax year in question.
3. **Write to HMRC** with details of the overpayment. Include your P60 figures and explain why you believe you have overpaid. AuditMyTax can generate a formal PAYE reconciliation letter that sets out your case clearly.
The 4-Year Deadline
You can claim back overpaid tax for the current year and the previous 4 tax years. As of 2026, that means you can go back to the 2021/22 tax year. If you have P60s from previous years, it is worth checking each one.
Key Takeaway
Your P60 holds the answer to whether you have overpaid. Take 5 minutes to check the numbers, either manually or using a free tool. If HMRC owes you money, the claim process is simple and you could have the refund in your bank account within a couple of weeks. Do not let it sit there unclaimed.