The short version
Both documents go out before the work starts, and both tell the customer what they can expect to pay. The difference is how firm the number is.
| Estimate | Quote | |
|---|---|---|
| What the price is | An approximation | A fixed number for a defined scope |
| Can it change? | Yes, if the work or materials change | Not without the customer agreeing to a change |
| Best for | Jobs with unknowns, repairs, hidden conditions | Jobs with a clear, repeatable scope |
| Customer expectation | A ballpark they can budget around | A number they can hold you to |
What an estimate is
An estimate says: based on what I can see, here is what I believe this will cost. It is the right tool when the job has unknowns. You cannot see inside the wall, the customer has not picked materials, or the scope may grow once work starts. The estimate gives the customer a realistic number to plan around while keeping both sides honest about what could change.
Because an estimate can move, the words around the number matter. State what the price is based on, list your exclusions, and put a validity date on it. How long is an estimate good for covers that last part.
What a quote is
A quote says: for exactly this scope, the price is this number. Once the customer accepts it, the understanding on both sides is that the number holds. That makes quotes powerful for winning work, because customers love certainty, and dangerous when you quote before you fully understand the job.
Only quote a fixed price when the scope is genuinely fixed. If you quote work with hidden conditions, you are betting your margin that nothing ugly is behind the drywall. When you do quote, write the scope tightly enough that anything outside it is obviously extra.
When to send which
Send an estimate when there are unknowns you cannot price: repairs, renovations, anything involving what is behind finished surfaces, or jobs where the customer is still deciding what they want. Send a quote when the job is well defined and repeatable, like a standard installation you have done many times with predictable materials and hours.
Plenty of contractors use a hybrid: an estimate for the first conversation, then a firm quote once the scope is pinned down and materials are chosen. Whichever label you use, put it on the document. The word at the top is what the customer remembers when the final number arrives.
Match the document to the certainty you actually have. Estimating when you should quote costs you margin; quoting when you should estimate costs you more.
What happens when the scope changes
Scopes change on almost every real job, so decide how you will handle it before it happens. The standard approach is a change order: a short written note describing the new work and the new price, which the customer approves before you do the work. It keeps a fixed quote fixed, and it turns an estimate revision into a conversation instead of a surprise on the invoice.
Whatever you send, the document itself should look the same: itemized lines, clear scope, plain terms. How to write an estimate walks through the whole process, and what to include in an estimate is the checklist version.