Quotation vs Invoice: What Is the Difference?
Learn when a quotation proposes scope and price, when an invoice requests payment, and how both documents fit into a clean sales workflow.
Introduction
A quotation and an invoice may contain similar line items, but they do different jobs. A quotation helps a customer decide whether to proceed. An invoice records an amount the seller is requesting after an agreed trigger.
A quotation is a proposal
A quotation describes proposed scope, price, assumptions, exclusions, tax treatment and validity. It is normally sent before work begins or goods are supplied. Until it is accepted, it should not be presented as money already owed.
An invoice is a payment request
An invoice is issued after the event agreed by both sides: delivery, completion, a recurring billing date, a deposit milestone or another contractual trigger. It carries an invoice number, issue and due dates, the amount payable and payment instructions.
The details that change
A quotation needs a valid-until date, acceptance route, delivery expectation and clear boundaries around the proposed scope. An invoice needs an unambiguous due date, payment reference and connection to the accepted quote, order or completed work. Changing “Quotation” to “Invoice” is not enough if the dates and terms still describe a proposal.
Example workflow
A repair business inspects equipment and sends quotation Q-104 for parts and labour, valid for 14 days. The customer approves it in writing. The business completes the work under job card J-208, then sends invoice INV-311 referencing Q-104 and J-208. After confirming payment, it issues receipt R-311. Each document explains a different stage without erasing the previous one.
When the price changes
If the customer requests extra work, revise the quotation or record an approved variation before invoicing. If an issued invoice must be reduced, use a credit note rather than silently replacing the invoice. Keeping the references connected creates a trail both parties can follow.
Which generator should you use?
Use the quotation generator while the customer is deciding and the invoice generator when payment is due. If a customer pays immediately, you may still need an invoice, receipt or regulated tax document depending on the transaction and local requirements.