Quotes and estimates — and how to turn one into an invoice
The difference between a quote, an estimate and an invoice, what a good quote includes, and how to convert an accepted quote into an invoice.
Last updated 14/06/2026
Winning work usually starts with a quote or estimate. Getting the wording right sets clear expectations and makes invoicing painless later.
Quote vs estimate vs invoice
- A quote is a fixed price you’re committing to for clearly described work. Once accepted, it generally becomes the agreed price.
- An estimate is your best approximation — useful when the scope isn’t fully known. Make clear it can change, and explain what would move the price.
- An invoice is your request for payment once the work (or an agreed stage) is done.
Whichever you send, label it clearly so the customer knows what they’re looking at.
What a good quote includes
- Your business and the customer’s details
- A unique quote number and the date
- A clear breakdown of the work and prices
- VAT, if you’re registered (so the total is the real total)
- A valid-until date — quotes shouldn’t be open forever; 30 days is common
- Any assumptions or exclusions, so there are no surprises
Turning an accepted quote into an invoice
When the customer says yes, you don’t start from scratch. Keep the same parties and line items, then issue an invoice with a fresh invoice number and today’s date. In the generator, switch the document type to Quote, send it, and later use Convert to invoice — it carries everything over and assigns a new invoice number, keeping your quote and invoice numbering separate.
Keep your numbering tidy
Use separate sequences for quotes and invoices (e.g. QUO-0001 and INV-0001) so nothing collides — the tool does this automatically. Invoice numbers in particular should be unique and sequential; see what a VAT invoice must include.
Frequently asked questions
What's the difference between a quote and an estimate?
A quote is a fixed price you commit to for the work described. An estimate is an informed approximation that may change once the work is better understood. Say which one you're giving so there's no confusion.
Is a quote legally binding?
Once a customer accepts a quote, it generally forms a contract at that price, so only quote what you're willing to stand behind. Estimates are not a fixed commitment, but you should still be reasonable and flag changes early.
Should a quote show VAT?
If you're VAT registered, show the VAT on the quote so the customer sees the real total. If you're not registered, there's no VAT to show.
How do I turn a quote into an invoice?
When the customer accepts, reuse the same details and issue an invoice with a new invoice number and date. The generator does this in one click with "Convert to invoice".
Ready to create your invoice?
Open the free generator →General information, not tax advice. Always check current HMRC guidance or consult an accountant.