A quotation is shared before work starts. An invoice is shared after products or services are delivered. Mixing these two documents can lead to delays, disputes, and payment confusion.

When to send a quotation

Send a quotation during the sales stage. It should include proposed scope, pricing, validity period, and assumptions. A quotation confirms expected cost; it does not request payment.

When to send an invoice

Send an invoice once work is completed or a milestone is delivered. It requests payment and includes invoice number, issue date, due date, tax details, and payment instructions.

Keep both documents aligned

To avoid disputes, make sure your invoice matches the approved quotation and contract terms. If scope changes, issue a revised quotation before billing.