Is a quote legally binding?

Generally, once a client accepts a quote it forms the agreed price and both parties are expected to honour it — you shouldn't raise the price and they've agreed to pay it. That's why quotes usually carry an expiry date and a clear scope. An estimate, by contrast, is only an approximation and is not binding.

What's the difference between an estimate and a quote?

An estimate is an approximate, non-binding figure given before the work is fully scoped — the final cost can change. A quote is a fixed price for clearly defined work that you commit to once the client accepts it.

Can I send an invoice without a quote first?

Yes, if the price was already agreed another way (a contract, an email, or a verbal agreement). The invoice should always match what the client agreed to pay. For larger jobs, sending a quote first avoids disputes about the amount.

Do quotes and estimates include tax?

They can show indicative tax, but they generally aren't tax invoices — and they don't by themselves create a VAT or GST reporting point, which depends on local time-of-supply rules. If you display tax on a quote, label it as estimated so it isn't mistaken for a tax invoice.

Invoice vs Quote vs Estimate: What's the Difference?

Three Documents, Three Jobs

Quotes, estimates, and invoices travel together through a project, but each does something different. Mix them up and you can either lose money (under-charging because you treated a quote as flexible) or lose a client (sending an invoice before they ever agreed a price).

Here's the short version: an estimate is your best guess at the cost, a quote is a firm price you commit to, and an invoice is the demand for payment once the work is done. They usually appear in that order.

What Is an Estimate?

An estimate is an approximate cost, given before the work is fully scoped. It signals "this is roughly what I expect this to cost" — useful when the job has unknowns, like a renovation where you can't see behind the walls yet.

Because it's a best guess, an estimate is usually not binding unless your contract says otherwise. The final figure can move up or down as the job becomes clearer. That flexibility is the point — but it also means you should make the "estimate" label obvious and note that the final cost may vary, so the client isn't surprised later.

Use an estimate when: the scope isn't locked down, materials or hours are uncertain, or the client just wants a ballpark before deciding whether to proceed.

What Is a Quote?

A quote (or quotation) is a fixed price for a clearly defined piece of work. Once the client accepts it, both sides are generally expected to honour that price — you can't quietly raise it, and they've agreed to pay it.

Because a quote commits you, only send one when you understand the job well enough to price it confidently. Include exactly what's covered, what isn't, and how long the quote stays valid ("valid for 30 days" is common, since your costs can change). A quote that accidentally leaves out a cost is a quote you may have to absorb.

Use a quote when: the scope is clear, you can price it accurately, and the client wants certainty before committing.

What Is an Invoice?

An invoice is a request for payment, issued after you've delivered the work (or at an agreed milestone). It's the only one of the three that's a formal accounting document: it carries a unique invoice number, payment terms, a due date, and — if you're registered — VAT or GST.

The invoice should match what the client already agreed to. If you sent a quote for £2,000, the invoice says £2,000. If you worked from an estimate and the final cost changed, the invoice reflects the actual work — and you should be ready to explain the difference. Our guide to writing an invoice covers every required field.

How They Fit Together

On a typical project the sequence runs: the client asks for a price → you send an estimate or a quote → they accept → you do the work → you send an invoice → they pay.

EstimateApproximate cost, not binding, sent before scope is final. Final price may change.

QuoteFixed price you commit to, sent before work starts. Usually has an expiry date.

InvoiceRequest for payment, sent after the work. Has an invoice number, due date, and tax.

Keeping the numbers consistent across all three is what makes you look organised. The estimate sets expectations, the quote pins down the price, and the invoice collects the money — same project, three stages.

A Note on Pricing Documents and Tax

Estimates and quotes are generally not tax invoices — they're commercial offers, so they don't by themselves create a VAT or GST reporting point. The actual tax point depends on your country's invoicing, payment, and time-of-supply rules. If you show tax on a quote, label it clearly as indicative so it isn't mistaken for a tax invoice.

Rules differ by country and situation, so if you're unsure how a deposit or an advance payment affects your tax point, check your local tax authority or an accountant.