Advance invoicing is a method in which a portion (based on a percentage) of a quote is invoiced upfront for products or services that have not yet been fully delivered and/or completed. This improves cash flow and reduces financial risks by spreading payments over the duration of the project.

At the final invoice, all advance invoices are settled and the remaining amount is calculated. The final invoice includes the details of the quote from which advance invoices were made, and the total amount per advance invoice is subtracted from the total quote amount to determine the remaining amount.