InvoiceInvoice vs Estimate vs Quote: What's the Difference?
Which document to send, and when
Updated September 24, 2026 · 3 min read
An estimate is an approximate price given before work begins, a quote is a fixed price you agree to, and an invoice is the request for payment sent after the work is done. Estimate and quote come first; the invoice comes last and is the document that actually gets you paid.
The short version
The three documents move in a sequence. An estimate or a quote comes first and agrees the price. An invoice comes last and asks for the money. Mixing them up is what leads to disputes about what was agreed.
| Feature | Estimate | Quote | Invoice |
|---|---|---|---|
| When it is sent | Before work | Before work | After work |
| Price | Approximate | Usually fixed | Amount now owed |
| Can it change? | Yes | Usually not | No |
| Its job | Give a ballpark | Agree the price | Get paid |
Estimate or quote: which one?
Use an estimate when you genuinely do not know the final figure yet — a repair where you cannot see the full problem, or a project whose scope may shift. Use a quote when the work is well defined and you can stand behind a fixed number.
From approved quote to invoice
Once the work is done, the invoice should not require starting from scratch. The client, the line items and the tax are already agreed — they just need to become a request for payment.
- Convert the accepted quote — Turn the approved quote into an invoice so the client, items and totals carry across automatically.
- Add an invoice number — Give the invoice its own sequential number, separate from your quote numbers.
- Set the due date and send — Add clear payment terms and send the PDF by email or message.
With an estimate maker that converts quotes into invoices, this takes a tap instead of a re-type. You can see how that works in Invoice Maker, and how the result is tracked once sent.
Key takeaways
- A quote is usually a fixed price; an estimate is an approximate one.
- Both come before the work, while an invoice comes after it.
- Converting an approved quote into an invoice saves retyping and keeps the numbers consistent.
Glossary
- Estimate
- An approximate price for a job, given before work begins, that may change if the scope or costs change.
- Quote
- A fixed price for a defined scope of work, which the client accepts before the work starts.
- Invoice
- A request for payment issued after goods or services have been supplied, showing what is owed and when it is due.
