Quote vs Estimate vs Invoice: What Is the Difference?

A quote is a fixed price for a job that the customer can accept. An estimate is an approximate price that may change once the work is done. An invoice is a request for payment, sent after the work is finished or the goods are delivered. Quotes and estimates come before the work; the invoice comes after.

Quote vs estimate vs invoice at a glance

	Quote	Estimate	Invoice
When	Before work	Before work	After work or delivery
Price	Fixed	Approximate	Final amount owed
Purpose	Win the job at a set price	Give an idea of cost	Get paid
Binding?	Usually, once accepted	No, but should be reasonable	Records a debt
Numbering	Q-0001	EST-0001	INV-0001

What is a quote?

A quote is a formal offer to do specific work for a specific price. When the customer accepts it, it normally becomes part of the contract, so the agreed price is what you invoice unless the scope changes. Use a quote when you can price the job accurately, such as a set number of web pages or fitting a known product.

What to include on a quote

• The word "Quote" and a quote number
• Your details and the customer's details
• A detailed description of the work and what is excluded
• The price, and whether it includes VAT
• How long the quote is valid, for example 30 days
• Payment terms, including any deposit

What is an estimate?

An estimate is your best guess at the cost when you cannot know the full scope in advance, such as repair work or open-ended consultancy. It is not a fixed price, but the final bill should not be wildly different. If the cost is going to rise, tell the customer before you continue.

What is an invoice?

An invoice asks the customer to pay for work completed or goods supplied. It should reference the accepted quote or estimate, so the customer can match the two. If you are new to this, start with what an invoice is and our invoice checklist.

From quote to invoice: a simple workflow

1. Send a numbered quote with a validity date.
2. Get the customer's acceptance in writing, even by email.
3. For larger jobs, request a deposit with a proforma invoice.
4. Do the work and record any agreed changes.
5. Send the final invoice, quoting the quote number and deducting any deposit paid.

Our free invoice generator can produce the final invoice in minutes; use the notes field to reference the quote number.

Example: when the job changes

A decorator quotes £1,500 to paint three rooms. The customer later asks for a fourth room. The decorator confirms a £450 extra by email before starting it. The final invoice shows £1,500 for the quoted work, £450 for the agreed extra and the £300 deposit deducted, so the balance due is £1,650. Clear records like this prevent almost all billing disputes.

Which should you use?

• Use a quote when the job is clearly defined and you want to win it on price.
• Use an estimate when the scope is uncertain and you need flexibility.
• Always send an invoice when the work is done, whichever you used first. Then see how to send it.

Frequently asked questions

Is a quote legally binding?

Once a customer accepts a quote, it usually forms a contract at that price, so you cannot normally charge more unless the job changes or your terms allow it. An estimate is not a fixed price, but the final bill should be reasonably close to it.

Can the final invoice be higher than the estimate?

Yes, an estimate is an approximate price. Tell the customer as soon as you know the cost will go up, explain why and get their agreement before continuing, to avoid disputes.

Does a quote need a number?

It is good practice. Number quotes in their own sequence, such as Q-0001, and refer to the quote number on the final invoice.

How long is a quote valid for?

As long as you say. State a validity period, such as 30 days, so you are not held to old prices if costs rise.

Is a quote the same as a proforma invoice?

No. A quote is an offer the customer can accept or reject. A proforma invoice is usually sent after agreement and before delivery, often to request a deposit or advance payment.