Quote, estimate, proposal or tender?
These four words get used interchangeably and they do not mean the same thing. The difference matters most at the exact moment you least want an argument — when the final cost has come in above the number the client remembers, and the entire question is whether that number was a commitment or an indication.
The distinction that actually matters
Strip away the terminology and there is one real question: did you make an offer the client could accept to form a contract, or did you give them information to help them decide? Everything else follows from that.
| Document | What it is | Can the price change? |
|---|---|---|
| Quote | A firm offer to do defined work for a stated price. If accepted while still valid, it typically forms a binding contract. | No — not without the client agreeing a variation. This is the whole point of a quote. |
| Estimate | A considered approximation of likely cost, given what is known now. | Yes, within reason. An estimate that lands at triple the figure will still be disputed, reasonably. |
| Proposal | A document arguing for an approach, usually including scope, method, timeline and price. | Depends entirely on how the pricing section is worded — it can contain either a quote or an estimate. |
| Tender / bid | A formal response to a structured invitation, typically on the buyer's terms and format. | Usually fixed, and often binding for a stated period whether or not you would still like it to be. |
The label alone will not save you. Writing “estimate” at the top of a document that then states a single confident price for fully defined work may still be read as an offer. What matters is whether the wording, read as a whole, looks like a commitment.
Making an estimate read as an estimate
If you genuinely cannot know the final cost, say so in a way that survives being read months later by someone who was not in the conversation.
- Give a range, not a point. A single number reads as a price no matter what you call the document.
- Name the assumptions. “Assumes the existing data is supplied in a single clean export” makes it visible what would change the figure.
- State the variables. Which specific unknowns could move the number, and roughly in which direction.
- Set a re-quote trigger. “If the scope changes materially, I will re-quote before continuing” is the sentence that prevents the difficult conversation later.
- Avoid false precision. An estimate of “£4,847” reads as a calculation someone stands behind. “£4,500–£5,500” reads as an estimate.
Making a quote safe to give
A firm quote is a genuinely good commercial instrument — clients prefer certainty and will often pay for it. It just needs boundaries.
- Define the scope tightly. A fixed price against a vague scope is the classic way to lose money on a job you were right to want.
- Put an expiry date on it. Your costs move. Thirty days is the usual default; shorter where materials or subcontractor rates are volatile.
- State what is excluded as explicitly as what is included. Exclusions prevent more disputes than inclusions do.
- Say how variations are handled — an hourly rate for out-of-scope work, or a commitment to re-quote. Without this, every change is a negotiation from zero.
- Reference your terms so that acceptance of the quote is also acceptance of your payment terms.
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What acceptance looks like
A quote becomes a contract when it is accepted — and acceptance is a lower bar than most people assume. An email saying “yes, go ahead” is usually enough. So, in many circumstances, is instructing you to start and letting you proceed.
Two practical implications. First, keep the acceptance: the message approving the quote is the single most valuable document you have if the invoice is ever disputed. Second, be careful about starting work on a verbal go-ahead while the written quote is still being revised — it is genuinely unclear afterwards which version was agreed, and that ambiguity tends to resolve against whoever is asking to be paid.
Common questions
Is a quote legally binding once accepted?
In most common-law jurisdictions an accepted quote functions as a contract, provided the usual elements are present. That is the deliberate purpose of calling it a quote rather than an estimate.
Can I withdraw a quote before it is accepted?
Generally yes, if you communicate the withdrawal before acceptance. Once accepted it is a contract, and withdrawing becomes a breach rather than a change of mind. Expiry dates exist so this rarely comes up.
How far over an estimate is too far?
There is no universal figure, and in some jurisdictions consumer rules require the final charge to be reasonable regardless of what was estimated. The practical answer is that you should be flagging the overrun as it happens, not presenting it as a finished number at the end.
Should a quote include tax?
Show it the way it will appear on the invoice. A quote excluding tax followed by an invoice adding 20% is one of the most common and most avoidable disputes in small-business billing.
What if the client accepts after the expiry date?
Then there is no live offer to accept, and you are free to re-quote. In practice most suppliers honour a recently lapsed quote and say that they are doing so — which is both goodwill and a reminder that the date meant something.
General information, not legal advice. Contract formation and the treatment of quotes and estimates vary by jurisdiction, and consumer contracts are often subject to additional protections. Take advice on anything significant.
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- Invoice payment terms explainedNet 30, EOM, 2/10 and what they cost you
- What to include on an invoiceThe fields that make it a valid record
- How to chase an unpaid invoiceA five-stage escalation ladder