Quote vs estimate — what's the difference?

People use “quote” and “estimate” as though they mean the same thing. They don’t, and the difference decides who absorbs the cost when a job turns out bigger than expected.

The short answer

• A quote is a fixed price you commit to for clearly described work. Once accepted, it is generally the agreed price — and any overrun is yours.
• An estimate is your best approximation of the cost, given what you can see. It can move as the work becomes clearer — and the risk sits more with the customer.

Side by side

	Quote	Estimate
Price	Fixed	Approximate
Binding once accepted?	Generally yes	No
Who carries overrun risk	You	Largely the customer
Best when	Scope is clear	Scope is uncertain
Can change?	Only by agreement	Yes, with good reason

Why the label alone doesn’t save you

Writing “estimate” at the top does not, by itself, make a document an estimate. What matters is the substance of what you communicated. A precise figure for precisely described work reads as a commitment whatever it is headed — and a customer who reasonably understood it as a fixed price has a decent argument.

A genuine estimate looks like one. It gives a range rather than a single figure where the range is real (“£1,400–£1,900 depending on the condition of the substrate”), it states the assumptions it rests on, and it says plainly what would change it.

Wording an estimate so it works

Three things do most of the work:

1. Say what you have assumed. “Assumes existing pipework is sound and accessible from the airing cupboard.”
2. Say what is excluded. “Excludes making good to plaster and any redecoration.”
3. Say what would move the price, and by roughly how much. “If the joists need replacing, allow a further £300–£450.”

A customer who receives that and goes ahead has accepted uncertainty with their eyes open. A customer who receives “about £1,500” and gets a bill for £2,100 has not.

When the job overruns

The rule is simple and almost always ignored: agree the change before you do the work, in writing — a text or email is enough. A variation agreed in advance is a normal part of the job. The identical sum presented at the end is a dispute, and one you may well lose on the facts even where the work was genuinely necessary.

If you quoted a fixed price and the job runs over, that is generally your cost unless the customer changed the scope or something was concealed and could not reasonably have been discovered. That is the trade-off you accepted in exchange for winning the work at a committed figure.

Working for a consumer rather than a business adds one more point. Under the Consumer Rights Act 2015, where a contract does not fix the price, the consumer is required to pay a reasonable price and no more. An estimate that has drifted a long way from the original figure with no agreed variation may be tested against that standard, so keep a record of what was agreed and when.

Which to use, in practice

Give a quote when you can see everything involved: a decorating job in an empty flat, a fitted wardrobe to a drawing, a fixed-scope design project. Committing to a price wins work, and if you have priced it properly the certainty is worth more to the customer than a lower opening figure.

Give an estimate when there are unknowns you genuinely cannot resolve first — a leak behind a wall, a rewire in a house of unknown vintage, an open-ended piece of research. Then convert it to a firm figure as soon as you can see properly, rather than letting the estimate quietly become the price by default.

Whichever you send, include a valid-until date. For what a good quote should contain and how to turn an accepted one into an invoice in one click, see quotes, estimates and invoices.