Quote vs Estimate: Which One Should You Send?
A quote is a price you're committing to. An estimate is your best read on a job you can't fully see. Sending the wrong one is how tradies end up doing work for free.
Most tradies use the words interchangeably, and most of the time it doesn't bite. Then a job opens up — the wall comes off, the switchboard turns out to be older than the house — and suddenly it matters a great deal which document you sent. A quote is an offer at a fixed price. An estimate is an informed guess. This guide covers the difference, when each is the right call, and what has to be in either one so the number holds.
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The difference in one table
| Quote | Estimate | |
|---|---|---|
| What it is | A fixed price you're offering to do defined work for | Your best assessment of likely cost |
| Once accepted | Forms an agreement — you're held to the price | Not a price commitment, but must be given honestly |
| Best for | Well-defined work you can see and scope | Work with genuine unknowns behind a wall or underground |
| Changing the price | Only through an agreed, documented variation | Update the client as the picture becomes clear |
| Risk sits with | You | The client, within reason |
Label the document plainly — the word "Quote" or "Estimate" at the top, not just in your head. If a client can reasonably read an estimate as a fixed price, you'll be arguing about it later, and the argument tends to go the way of whoever wrote the ambiguous document.
When to send a quote
Quote when you can see the whole job. If you've been on site, measured it, checked access and know what you're connecting to, a fixed price is the stronger document — it's easier for the client to say yes to, and it lets you keep the upside when the job runs well.
- Replacing like for like — a hot water system swap, a fence line you've walked.
- Work you do constantly and can price from experience.
- Anything the client is comparing against other tradies — a firm number wins over a range.
- Jobs where the scope is genuinely closed and you've confirmed it in writing.
The trade-off is that the risk is now yours. That's fine when you can see the job — it's why you carry a contingency in the number rather than hoping.
When to send an estimate
Estimate when something material is genuinely unknown and can't be found out before you start. The honest version of this is not hedging — it's telling the client exactly what you can't see yet and what would change the number.
- Renovation strip-outs where what's behind the wall decides the work.
- Underground services and drainage you can't confirm until you dig.
- Old switchboards and wiring where compliance work may cascade.
- Damage repairs where the extent isn't visible until you open it up.
- Insurance and make-good work with scope still being agreed.
An estimate with no stated basis is worthless to both sides. Say what it assumes — "assumes existing circuit is serviceable", "assumes no rock below 300mm" — so when the assumption fails, the conversation is about a known variation rather than a broken promise.
What has to be in either document
Whichever you're sending, the same items decide whether the number holds when the job gets complicated:
- Your business details — name, ABN and contact, and your licence number where your trade requires it.
- The client and the site address — the job, not just the person.
- Itemised scope — what you're doing, broken into lines rather than a lump sum.
- Exclusions — what you're not doing. This is the line that prevents most disputes.
- Materials and who supplies them — including who's responsible if client-supplied goods are wrong.
- GST — shown clearly, so the total isn't a surprise.
- Validity period — how long the price holds. Supplier prices move.
- Payment terms — deposit, progress payments, and when the balance falls due.
- Variation process — how extra work gets agreed and priced before it's done.
Exclusions and the variation process are the two that tradies leave off most often, and they're the two that cost the most when a job turns. Write them once, save them, and put them on everything.
Handling the change when it comes
The moment the job differs from what you priced is the moment to deal with it — not at invoicing. Verbal variations are the single most common way tradies lose money on otherwise good jobs.
- Stop and price it. Work out what the change costs before you do it, not after. Ten minutes now saves the argument later.
- Put it in writing. A text or an emailed variation line is enough. What matters is that it exists and the client has seen the number.
- Get a yes. Explicit approval before the work happens. "Just do what you need to" is not a price agreement.
- Attach it to the job. Keep the variation with the original quote so the invoice can be built from both and nothing is reconstructed from memory.
ServiceYak builds itemised quotes from your saved rates, keeps exclusions and terms on every one, and carries the accepted quote plus any variations straight through to the invoice — so what you charge matches what you agreed.
Frequently asked questions
What's the difference between a quote and an estimate?
A quote is a fixed price offer for defined work — accept it and you're held to that price. An estimate is your best assessment of likely cost where something is genuinely unknown, and isn't a commitment to that figure. The practical difference is who carries the risk when the job turns out bigger than it looked.
Can I change a price after the client accepts a quote?
Not unilaterally. Once a quote is accepted you've agreed a price for the scope described, so the only clean route is a documented variation the client approves before the extra work happens. That's exactly why exclusions and a stated variation process belong on every quote you send.
How long should a quote stay valid?
Long enough for the client to decide and short enough that supplier prices haven't moved — commonly 14 to 30 days. Put the date on the document. Without one, a client can accept a six-month-old price and reasonably expect you to honour it.
Should I send an estimate to win the job and quote later?
Only if the unknowns are real. Using an estimate to look cheap and firming up afterwards damages trust and tends to end in a dispute. If you genuinely can't see the job, say so and state your assumptions; if you can, quote it properly and back your number.