How To Legally Update a Quote for Your Business Contracts in Australia

Quoting is part of everyday life for Australian businesses, especially when each job or project is a little different. You give a client a number, outline the scope, and set expectations. But what if circumstances change before they accept-materials go up, scope changes, or you spot an error?

Updating a quote the right way isn’t just good customer service. It’s how you manage risk, avoid disputes, and make sure you and your client are genuinely on the same page before a contract forms.

In this guide, we’ll walk through when quotes become binding, how to legally update a quote, what to include in your revised document, and how Australian Consumer Law (ACL) can affect your approach. We’ll also cover the documents and processes that make quoting smoother and safer for your business.

What Is a Quote and When Is It Binding?

In most cases, a quote is simply a price and scope proposal you give to a prospective customer. It sets out key details-what you’ll deliver, the cost, and any assumptions. Legally, a quote by itself is usually treated as an invitation to treat, which means it invites your customer to make an offer rather than being a binding offer itself.

However, context matters. A quote can become binding if it looks and behaves like an offer and the customer accepts it. This is more likely if:

• Your quote is detailed and covers all essential terms (scope, price, timing, payment).
• The client accepts the quote in writing or starts relying on it in a significant way.
• Your industry practice or communications suggest your quotes are firm offers.

If those factors are present and the client accepts, the quote can form a contract. For more on when this line is crossed, see our explainer on whether a quotation is legally binding.

Acceptance doesn’t have to be complicated either. It might happen by signing your quote, replying “yes” by email, or otherwise agreeing to your terms. If you’re relying on email confirmations in your business, it’s worth understanding when an email can be legally binding in Australia.

Why You Might Need to Update a Quote

Plenty of legitimate business reasons can prompt a quote update before a client accepts, including:

• Material cost increases: Supplier or fuel prices rise after your initial quote.
• Scope changes: The client adds items, changes materials, or alters timelines.
• Errors or omissions: A miscalculation or a missing component needs correction.
• Delays: If a client takes a long time to respond, your costs or capacity may have shifted.
• Subcontractor updates: New rates or availability from your contractors impact pricing.

If any of these arise before acceptance, updating the quote promptly-and clearly-is both good practice and a legal safeguard.

How To Legally Update a Quote (Step-By-Step)

1) Act Before the Client Accepts

The safest time to change a quote is before it’s accepted. Once a client accepts (by signature, email, deposit, or other clear agreement), the quote may form part of a binding contract. Unilateral changes after that point can expose you to breach of contract risks unless the client agrees to a variation.

2) Explain the Reason-In Writing

Tell the client you need to revise the quote and explain why. Keep it straightforward: material price increases, scope changes, or correcting an error. Written communication (email is fine) helps keep a clean paper trail and avoids confusion later.

3) Issue a Clearly Marked “Revised Quote”

Send a fresh document labelled “Revised Quote” or “Updated Quote,” with a new date and version number if you use them. Make it easy to see the differences so there’s no ambiguity about which document applies.

• Include the client’s details, a clear scope, updated price, payment terms, and assumptions.
• Add or restate a validity period/expiry date so the update doesn’t sit open indefinitely.
• Note that the previous quote is withdrawn or superseded (to avoid parallel versions).

If you regularly quote, consider standardising your terms using a robust quote template or pairing your quote with light “quote terms” so expectations are consistent from job to job.

4) Get Explicit Written Acceptance

Ask the client to confirm acceptance of the revised quote in writing. This could be a reply email, electronic signature on the quote, or a simple signed acceptance page. If you want even more certainty for key terms or initials next to changes, you can ask clients to initial the updated parts-see our tips on how to initial a document effectively.

Where you accept approvals by email, make sure you’re comfortable with how and when emails can create binding agreements.

5) Keep Your Contracts in Sync

If a separate contract will follow (or is already in place), make sure the numbers, scope and timelines match. For services work, it’s common to capture the final agreed scope and price in a Service Agreement or Statement of Work. Consistency across your documents is key to avoiding disputes.

6) Store the Paper Trail

Keep copies of the original quote, the revised version, and all related emails or messages. If there’s ever a disagreement, a clear trail of versions and acceptance is your best friend.

Validity, Estimates vs Quotes, and Consumer Law

Set a Validity Period on Every Quote

Including a validity period protects you from changing costs and keeps expectations clear. A common approach is: “This quote is valid for 14/30 days from the issue date.” If it expires, issue a new version with updated pricing or assumptions.

If you ever need to withdraw a quote early, do so in writing before the client accepts, and mark the previous version as void.

Know the Difference: Estimate, Quote, Invoice

• Estimate: A rough price guide where final costs may change as details firm up.
• Quote: A more definite price for a specific scope that can become binding once accepted.
• Invoice: A request for payment after you’ve delivered the work or reached a milestone.

Label your documents clearly so clients understand what stage they’re in. Calling an estimate a “quote” (or vice versa) can cause confusion and disputes.

Stay Onside With Australian Consumer Law (ACL)

The ACL prohibits misleading or deceptive conduct. In practice, that means you should avoid giving quotes you can’t meet, update clients quickly if something material changes, and be upfront about inclusions and exclusions. For a deeper dive on this concept, see our plain-English guide to section 18 of the Australian Consumer Law.

Transparency goes a long way. If you need to lift the price, explain why and seek agreement before proceeding. Sudden increases after acceptance, without consent, can create both consumer law and contract law issues.

Documents and Processes To Support Your Quotes

Strong templates and simple processes make quoting and revisions faster, clearer and legally safer.

• Quote Template and Terms: Use a consistent format with scope, assumptions, expiry, payment terms and acceptance instructions. If you publish general trading terms, ensure your quote references those terms or attach your Business Terms where appropriate.
• Service Agreement or Customer Contract: For more complex work, a signed Service Agreement can sit alongside the quote to lock in deliverables, timelines, payment, warranties, liability and dispute resolution.
• Variation or Amendment Process: If scope or price needs to change after acceptance, get agreement in writing using a simple variation form or amendment letter. If you need to change a contract after it’s been signed, follow best practice for making amendments to contracts.
• Acceptance Protocol: State clearly how a client can accept (e.g. e-signature, reply email, purchase order). This reduces uncertainty and speeds up onboarding.
• Privacy Practices: If you collect personal information to prepare quotes or onboard clients, you must handle that information in line with the Privacy Act 1988 (Cth). A Privacy Policy is legally required if you’re an APP entity (for example, most businesses with annual turnover of $3 million or more, or certain businesses handling sensitive information). Even if you’re not required to have one, many businesses adopt a Privacy Policy as best practice for transparency and customer trust.
• Records and Version Control: Keep all versions of quotes, acceptance emails and related messages in one place. You’ll save time later if questions arise.

If quoting is a central part of your workflow, it’s worth investing in your standard templates and processes early. A small amount of setup now can save many hours-and headaches-over the long run.

Key Takeaways

• A quote is usually an invitation to treat, but it can become binding once accepted, especially if it contains all essential terms.
• If you need to change a quote, do it before the client accepts, explain the reason in writing, and issue a clearly labelled “Revised Quote”.
• Ask for explicit written acceptance of the updated quote-reply email, e-signature, or initials next to key changes can all help confirm agreement.
• Align your quote with your downstream documents. For services work, keep your quote consistent with your Service Agreement or scope of work to avoid mismatches.
• Use a validity period to reduce the risk of old quotes being accepted after market conditions change, and be clear about inclusions and exclusions.
• Be mindful of the ACL-avoid misleading statements, update clients quickly, and secure consent to any price changes after acceptance.
• When a signed contract needs changing, follow a proper variation or amendment process rather than changing terms unilaterally-see our guidance on contract amendments.

If you would like a consultation on managing or updating quotes for your business contracts, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no-obligations chat.