How to Claim Back Overpaid Tax via Self Assessment

Overpaying tax is more common than you might think. Emergency tax codes, incorrect PAYE calculations, or simply not claiming all your expenses can leave you out of pocket. Here is how to get your money back.

Common Reasons for Overpayment

• Wrong tax code applied by your employer
• Not claiming all allowable business expenses
• Paying tax on a redundancy payment that should have been tax-free
• Emergency tax code when starting a new job
• Not claiming the Marriage Allowance
• Payments on account that exceeded your actual tax bill

How to Check

If you file Self Assessment, your tax calculation shows whether you have overpaid. Compare the total tax due with the total tax already paid (through PAYE and payments on account). If you have paid more than you owe, you are due a refund.

Accounted shows your real-time tax position throughout the year, so you always know whether you are on track, overpaying, or underpaying.

How to Claim a Refund

Through Self Assessment: If your return shows an overpayment, HMRC automatically processes a refund. You can choose to have it:

• Paid into your bank account (fastest — usually within 5 working days of processing)
• Applied against future tax liabilities
• Sent by cheque (slowest)

Outside Self Assessment: If you are not in Self Assessment (for example, you only have PAYE income), contact HMRC or use form R40 to claim a refund.

How Long Can You Claim Back?

You can claim overpaid tax for up to 4 years after the end of the tax year. For example, overpaid tax from 2022/23 can be claimed until 5 April 2027.

Speed Up Your Refund

File your Self Assessment return early — the sooner you file, the sooner HMRC processes your refund. Ensure your bank details are up to date in your HMRC account for direct payment.

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