Duplicate Invoices are a common accounting issue that can cause confusion and lead to money being wrongly allocated. The official business definition of duplicate invoices is an invoice for the same product or service that is sent to a customer twice. This can occur when a customer is sent a second invoice for goods or services they have already paid for, or when an invoice is erroneously sent out due to a double entry.

Duplicate invoices can also be generated if a customer requests a copy of an invoice they have already received. In any of these cases, the customer can be expected to pay both invoices, creating an unnecessary expense to the business. To prevent duplicate invoices, businesses should ensure they have an efficient invoicing system with clear processes in place, including a double-check of all invoices before they are sent out.