Most service-business owners use 'estimate' and 'quote' interchangeably. Customers do too. But in contract law and in customer-perception terms, they mean very different things — and using the wrong word at the wrong time is the easiest way to either give away margin or end up in a small-claims hearing.
The legal difference. An estimate is an opinion of probable cost. It is not a binding price. A reasonable variance (often 10–25%) is expected and accepted. The contractor is not legally required to honor the original number if scope expands or costs change.
When to use 'estimate'. Renovation work where you can't see behind the walls
When to use 'quote'. Install a defined product (water heater, dishwasher, light fixture)
How to write each document. An estimate document must state 'ESTIMATE — subject to change based on actual scope.' Include a variance allowance (e.g., '±15% expected variance'). Define what triggers a change order.
Frequently asked questions
Can I turn an estimate into a quote?
Yes — once scope is locked. Do an inspection or partial demo, then issue a firm quote for the remaining work. Customers appreciate the upgrade from uncertainty to certainty.
What if the customer agreed to an estimate and now disputes the higher final bill?
Document the scope changes and material price changes in writing as they happen. If you didn't, the customer has a good argument that you should honor the original number.
Is a verbal quote binding?
In some states, yes — for small amounts. In most states, written quotes are required above a threshold. Never give a binding verbal quote on anything material; send a written follow-up the same day.
