Estimate vs Quote: What's the Difference (and When to Use Each)?

A customer asks what a job will cost. You write a number on a form and send it. Whether that number is a quote or an estimate decides something most trades never think about until it goes wrong: whether you can charge what the job actually costs, or whether you're locked into the figure you guessed at on the doorstep. The two words get used interchangeably in conversation, but in business — and in law — they are not the same thing.

The core difference in one line

A quote is a fixed price you commit to. An estimate is your best, honest guess that can change. Once a customer accepts a quote you've effectively agreed a price for the work, and you can't simply bill more later because your costs rose. An estimate sets an expectation, not a ceiling — but the final bill still has to be reasonable, and a figure that balloons far past the estimate is one the customer can dispute.

In the UK this distinction has teeth. Citizens Advice spells it out: a quote is a promise to do the work at an agreed price, and a trader can't charge more than they quoted unless the customer agreed to extra work or the quote contained an obvious mistake — rising costs alone don't count. An estimate, by contrast, is the trader's best guess, and if the final bill comes in much higher the customer can challenge it and pay only what's reasonable. The official consumer guidance is on Citizens Advice's page on getting building work done.

The same logic holds in the US, Canada and Australia even where it isn't written into a single statute: a quote the customer accepts becomes the agreed price of the contract, while an estimate is understood to be approximate. The safest rule everywhere is to label the document clearly, so there's no argument later about which one you sent.

When to send a quote

Send a quote when you can see the whole job and price it with confidence.

• The scope is clear and unlikely to change — replacing a known set of sockets, fitting a supplied appliance, a fixed package of design work.
• You've seen the site or the full brief, so there are no hidden unknowns waiting to inflate the cost.
• The customer wants certainty and is comparing fixed prices — a clear quote often wins the job over a vague “it depends”.
• Material prices are stable, or you can lock them in quickly before they move.

When to send an estimate

Send an estimate when honest unknowns make a fixed price a gamble you'd lose.

• You can't fully inspect the job yet — what's behind the wall, under the floor, or inside the system is unknown.
• The work depends on choices the customer hasn't made yet, such as final fittings, finishes, or quantities.
• It's time-and-materials work where the hours genuinely depend on what you find.
• You're giving a ballpark early in a conversation so the customer can decide whether to take it further.

How to word each so it protects you

The label is only half the job; the wording is the other half. On a quote, state exactly what's included and — just as important — what isn't, so any extra work is clearly outside the agreed price, and add a validity period such as “valid for 30 days” because your costs and availability change. On an estimate, say plainly that it's an estimate and not a fixed price, and explain what could move the number: “Estimate based on the visible work; if additional work is needed, we'll agree any extra cost with you before proceeding.” That one sentence is the difference between a reasonable variation and an angry dispute.

From quote or estimate to invoice

Both documents are the front end of the same job; the invoice is the back end. When the work is done, the invoice should mirror the quote line for line, so the customer can see they're being charged exactly what they agreed. If you sent an estimate and the final figure moved, itemise why — the original lines plus a clearly labelled variation — so the increase is transparent rather than a surprise. Keeping the same descriptions across quote, estimate and invoice also makes your own bookkeeping far easier at year end. Our guides on writing a quotation and on the invoice, receipt and quotation trio cover the next steps.

Get this one habit right and a whole category of payment arguments disappears: decide, before you send the number, whether you're making a promise or a prediction — then label it, word it, and bill it accordingly.