A Commercial Invoice is used to record accounts receivable for the seller and accounts payable for the buyer. The content of the Commercial Invoice is almost always the same as the Pro Forma Invoice. However, the final sale price may vary with the Pro Forma Invoice, as the Pro Forma Invoice is issued before an actual sale takes place. Its purpose is to give a customer a clear idea of what to expect, and it acts as a good faith estimate showing what can be known in advance, such as prices and terms, and an average billing amount for the types of items being requested. A customer may also use a Pro Forma Invoice to decide whether or not to place an order. The purpose of a Commercial Invoice is to request payment for items that have actually been sold by showing the amount that should be paid.