Quote vs Estimate vs Invoice: Which Should You Send?

Send an estimate when you need to describe an approximate cost with unresolved assumptions. Send a quote when you can offer a defined scope at a stated price. Send an invoice when you are requesting payment for an agreed charge, including a deposit or milestone where applicable.

These names explain the commercial purpose of a document. Its legal effect depends on the wording, acceptance, agreement and applicable law. An invoice alone does not turn unapproved work into a debt, and calling a document an “estimate” does not override promises made elsewhere.

Compare the three documents

Question	Estimate	Quote	Invoice
What does it communicate?	Expected cost and assumptions	Offer for a stated scope and price	Details of a billed charge
When is it useful?	Before the scope is settled	Before the customer accepts the offer	At the agreed billing event
How is price presented?	Approximate amount, range or basis	Specified amount subject to stated terms	Amount charged and balance payable
Key supporting details	Unknowns, exclusions and change process	Inclusions, exclusions, validity and acceptance	Invoice number, dates and payment details
What follows?	Scope clarification or a quote	Acceptance or revision	Payment, query or correction

Use an estimate when you cannot fix the scope

An estimate helps the buyer plan while you identify the work. Explain what information is missing and what could change the price. For hourly work, include an expected number of hours and a rate rather than an unexplained total.

For example: “Estimated 12–18 hours at $75/hour, total $900–$1,350 before any applicable tax. Assumes the existing website can be edited without rebuilding its theme. Paid plugins and new pages are excluded. We will seek approval before exceeding the estimated hours.”

That explanation gives the customer a useful budget and a point at which to review the scope. Choose a range based on your actual assessment; the fictional figures here are not recommended prices. Use the estimate generator to prepare the document and put assumptions in its notes or terms.

Use a quote for a defined offer

A quote should make the offer understandable without a separate conversation. Describe deliverables, quantities, included revisions, exclusions, taxes, payment stages and the validity period. State how the customer should accept it and when work can begin.

For a website update, a quote might offer five named page changes and one revision round for $1,200, excluding hosting and additional pages. An extra revision should follow the agreed change process instead of appearing as a surprise charge at the end.

Keep the accepted version and written acceptance. If pricing changes before acceptance, issue a revised quote with a revision reference and identify which version replaces the earlier offer. Do not quietly edit the version already received by the client.

Use an invoice at the agreed payment stage

An invoice does not always wait until completion. It may bill an agreed advance, a completed milestone, delivered goods or a service period. Reference the quote, order or contract so the buyer can match the charge to its approval.

Include a unique invoice number, issue date, applicable supply details, line items, currency, total, recorded payments and due date. See how to make an invoice for the full workflow.

Worked project: estimate to quote to invoice

This fictional USD project excludes taxes to keep the comparison clear.

1. Estimate EST-0012: $900–$1,350 for a website update, depending on the final page list.
2. Quote QT-0018: agreed scope is fixed at $1,200, with a $300 advance and $900 payable at completion.
3. Advance: issue the appropriate payment or tax document for the $300 under your local rules, and record receipt when it arrives.
4. Change approval: the customer accepts a separate $150 addition in writing.
5. Final invoice INV-0042: total project charges are $1,350. If the advance was only recorded as a payment against this transaction, show the $300 received and $1,050 balance due.

If you already issued a separate invoice for the $300 advance, reconcile it when making the final bill. You may need to invoice only the remaining charges or use a prescribed adjustment process. Do not bill $1,350 again without accounting for the earlier invoice. The correct tax handling depends on the jurisdiction.

Converting a saved quote in this app

Save the quote to Documents first. Open it and select Invoice from the document-type control. The editor creates a new document identity and invoice number while carrying across customer details and items. Previously saved source documents remain available.

Before sending the new invoice, check the issue date, due date, terms, tax treatment and PO reference. Conversion preserves existing dates and terms, so they may still describe the original offer. Payment records reset when the type changes; add confirmed payments to the invoice as appropriate. Save and export the new document separately.

Questions that prevent pricing disputes

• Is the price approximate or a stated offer for the described work?
• Does the customer understand the inclusions and exclusions?
• Who can approve a change, and how is approval recorded?
• Are deposits and previously invoiced milestones reconciled?
• Does the invoice match the accepted version and approved changes?

If a client disputes a charge, compare the accepted scope, delivery evidence and change approvals before changing the bill. A clear record is more useful than relying on the document title.

Official guidance and legal scope

New Zealand Consumer Protection explains quotes and estimates, including price expectations and agreeing changes. It is guidance for that jurisdiction, not a worldwide contract rule. Check the law that governs your agreement for binding terms, consumer protections and disputes. GOV.UK’s invoice checklist covers UK invoice particulars.