Quote vs Estimate vs Invoice: Which to Send and When

A quote is a fixed price for a defined job, an estimate is an approximate price before the scope is settled, and an invoice requests payment once the work is done. In order: estimate to explore, quote to commit, invoice to get paid.

These three get used interchangeably, and it quietly costs people money. Call an estimate a “quote” and a client will hold you to a number you meant as a ballpark. Send an invoice when you meant to quote and you look like you’re billing for work you haven’t done. Here’s the clean version.

What is an estimate?

An estimate is a best-guess figure you give before the scope is fully known. It signals roughly what the work will cost and is not binding — ideal early in a conversation when the details might still change.

What is a quote?

A quote (or quotation) is a firm, committed price for a clearly defined scope. Once the client accepts it in writing it generally becomes the agreed price, so only send one when you understand the job well enough to stand behind the number.

What is an invoice?

An invoice is sent after the work is done, or at agreed milestones, to request payment. It’s a binding accounting document and the basis for your records and tax — see how to write an invoice.

Quote vs estimate vs invoice, side by side

	Estimate	Quote	Invoice
Price	Approximate	Fixed	The amount due
Binding?	No	Yes, once accepted	Yes, payable
Stage of the job	Early, still scoping	Scope is clear	After delivery
Can it change?	Yes, freely	Not once accepted	No
Has a due date?	No	No	Yes
Turns into	A quote	An invoice	A receipt once paid

The usual order

• 1. Estimate — a rough price while you scope the work.
• 2. Quote — a fixed price once the scope is clear.
• 3. Invoice — bill the agreed amount after delivery.

A quick example

A client asks what a kitchen refit costs. Early on you give an estimate of “around $6,000”. After a site visit you send a quote for a firm $6,450. When the job’s done you send an invoice for $6,450, due in 14 days. Three documents, one job, each doing a different thing.

Where a proforma invoice fits

For advance-payment or export deals, a proforma invoice sits between the quote and the final bill — it confirms terms before payment or shipping without being a tax invoice. More on that in proforma vs commercial invoice.

Create each for free

Send a quote or estimate to win the job, then turn it into an invoice when the work is done. Want to see the layout first? Here’s a quote example.

Frequently asked questions

Is a quote or an estimate binding?

A quote is binding once the client accepts it; an estimate is approximate and not binding.

Can an estimate become a quote?

Yes. Once the scope is clear, firm up the estimate into a fixed quote the client can accept.

Can I turn a quote into an invoice?

Yes — reuse the same line items in an invoice once the client accepts the quote and the work is delivered.

What is the difference between a quote and a proforma invoice?

A quote wins the work with a fixed price; a proforma invoice confirms terms before payment or shipping, often for advance payment or export.

Written by the FreeBillKit team. Last reviewed July 2026.