Estimate vs quote vs invoice: what to send, and when
Three documents, three completely different legal weights. Contractors lose money on this distinction more often than on any other paperwork mistake — usually by writing the word “quote” on a number they meant as a rough guess.
The one-line version
| Estimate | Quote | Invoice | |
|---|---|---|---|
| What it is | Your best guess at the cost | A fixed-price offer | A demand for payment |
| Can the price change? | Yes, within reason | No, once accepted | No |
| Binding? | Generally not | Becomes a contract when accepted | Reflects work already agreed |
| Send it | Before you have full information | When the scope is nailed down | After the work, or at agreed stages |
| Must include | A variance note | An expiry date | Payment terms & due date |
Estimate: a guess you are allowed to be wrong about
An estimate is your informed prediction of what a job will cost. You give one when you genuinely cannot know the final number yet — the wall is still closed, you have not pulled the panel cover, the slab has not been exposed. Because it is a prediction rather than a promise, an estimate does not normally bind you to that figure.
That protection is not automatic, though. It comes from the document saying so. An estimate that is silent about variance reads to a customer — and often to a small-claims judge — like a price. Two lines fix it:
- Label the document Estimate at the top, not “Quote” and not just “Price”.
- State the variance and the trigger: “This is an estimate based on a visual inspection. If concealed conditions require additional work, we will stop and issue a written change order before proceeding.”
The second half of that sentence matters more than the percentage. What protects you is the promise to stop and get written approval, not a vague claim that costs may rise.
Quote: a fixed offer with a shelf life
A quote is an offer to do a defined scope for a defined price. When the customer accepts it, you have a contract, and you are on the hook for that number even if your supplier raises copper 8% the following week. Quote only when you have measured, when the scope is genuinely fixed, and when you have priced materials recently.
Two things keep a quote from becoming a trap:
- An expiry date. “Valid for 14 days” is standard and is the single most useful line on the document. Without it, a customer can accept a quote you wrote before a material price jump and hold you to it.
- A scope boundary. Write what is excluded, not only what is included. Permit fees, drywall repair, disposal of the old unit, and after-hours work are the classic four that get assumed into a price they were never in.
Invoice: the document that actually gets you paid
An invoice is not a summary of the job. It is a request for a specific amount by a specific date, and it should be boring and unambiguous. It needs a unique invoice number, the date issued, the amount due, the due date stated as an actual date rather than “Net 30”, and exactly one obvious way to pay.
If you took a deposit, show the arithmetic: total, less deposit received, balance due. Customers dispute invoices they cannot reconcile against what they already paid, and that dispute costs you more in chase-up time than the discount you were worried about.
The sequence that avoids arguments
- Estimate at the first visit, when you are still discovering the job.
- Quote once the scope is fixed — a firm price, an expiry, and clear exclusions.
- Change order the moment anything moves. Written, signed, before the extra work happens. This is the step everyone skips and it is the one that causes the fight.
- Invoice on completion or at agreed stages, referencing the accepted quote number.
A note on written-contract rules
Many US states have home-improvement contract requirements that kick in above a dollar threshold — a written, signed agreement, specific disclosures, sometimes a cancellation window. The thresholds and the required wording vary by state and change periodically, so treat this page as the practical framework and confirm the specifics with your state contractor licensing board before relying on them. The habit of putting the scope, price, and change-order process in writing satisfies the spirit of essentially all of them.
Build any of the three in about a minute
QuoteKit is a free browser tool that produces all three documents — estimate, quote, or invoice — with the right labels, expiry and totals for each. Nothing is uploaded; it runs entirely on your device.
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