Quote vs estimate — the difference that costs money

A quote is a fixed offer

Once the customer accepts a quote, that is the price. You cannot raise it because the job took longer than you thought or because copper went up. If you want to change it, you need agreed variations in writing.

Quote when the scope is clear and visible: a bathroom suite swap, a rewire of a known property, a fence run you have measured.

An estimate is an informed guess

An estimate signals that the final figure may move. It is the right document when you cannot see the whole job — behind tiles, under floors, inside an old system — or when the customer is still choosing materials.

To keep it an estimate rather than an accidental quote, say so on the document: label it "Estimate", state that the final price depends on the conditions found, and give the range or the hourly and material basis you will charge on.

Side by side

• Binding? Quote: yes, once accepted. Estimate: no, but it must be given in good faith.
• Scope known? Quote: fully. Estimate: partly.
• Risk sits with: Quote: you. Estimate: the customer.
• Customer confidence: Quote: high. Estimate: lower, so expect more questions.

How much can an estimate move?

There is no fixed legal percentage, but a final bill wildly above the estimate is a consumer dispute waiting to happen. Tell the customer as soon as you know the figure is moving and get their agreement before the extra work happens — not on the invoice.

Practical rule of thumb

If you would be comfortable doing the job for the number you are about to write, quote it. If you would only be comfortable with a get-out, estimate it and say why. Customers respect an honest "I can't price the pipework until the floor is up" far more than a number that changes later.