Glossary · Invoices and billing
Overpayment
An overpayment is a customer payment larger than the amount owed, leaving a credit on their account to refund or apply.
Overpayments happen when a customer pays an invoice twice, pays before a credit note was applied, or pays a round sum. The excess sits on their account as a credit balance.
Don’t quietly keep it. Tell the customer, and either refund it or, with their agreement, apply it to the next invoice. Unresolved credits make your statement and theirs disagree, and can turn into a dispute later.
Duplicate payments are worth a look on your side too: they often mean the customer’s accounts-payable team had two copies of the same invoice, which points to a delivery or numbering problem.
Example
A client pays a £2,400 invoice twice. The supplier emails the same day offering a refund or a credit against next month’s £2,400 invoice, and the client chooses the credit.