A quote is an offer. An invoice is a bill. Sending the wrong one is how jobs sit unpaid, or get argued after the work is done.
Bathroom exhaust fan and four downlights
Valid 30 days. No due date. Nothing is owed until this is accepted.
Bathroom exhaust fan and four downlights
Due in 14 days. Includes the approved variation for chasing existing wiring.
Same bathroom at 14 Oak Street. The quote went out after the site visit. The invoice went out after the fan was in - plus a variation the client signed on the day.
A quote says: this is what we will do, for this price, if you say yes. It can expire. It has no due date. Nobody owes you anything while it sits in their inbox.
An invoice says: this money is now due. It needs a due date, a tax treatment, and a number you can chase. It belongs after the client has agreed - a deposit before you start, or the balance when the work is done.
The mix-up is rarely philosophical. Someone types the price into a Word doc, writes Invoice at the top because that is the only letterhead they have, and then wonders why the client treats it as a maybe.
Put the job, the site, the line items, and the total on both. After that they diverge.
The quote needs a validity window (price holds 30 days), the exclusions (does not include chasing existing wiring, asbestos, or after-hours), and a way to accept - a reply, a button, a signed PDF. If they cannot say yes on the document, it is a brochure.
The invoice needs a due date, how to pay, and a reference back to the quote or work order it came from. If you took a deposit, show it as a line that reduces the balance. Do not make them reconstruct the job from memory.
Needing materials money before you start does not turn the quote into an invoice. It adds a second document. Quote first. Accept. Then a deposit invoice - often 30% or the cost of the special-order parts - against that quote. The remaining balance stays visible on the job so nobody is surprised on the last day.
Sending only a deposit invoice, with no quote on file, is how you end up arguing about what the rest was supposed to cover.
On 14 Oak Street the ceiling was lined. The quote excluded chasing. Once the fan hole was cut, the existing cable was 1.5m short. That is a variation: write it, price it, get a yes, then add it to the invoice. The original quote stays true. The invoice shows quote plus variation, not a new made-up total.
If you skip that step and just invoice $1,265 against a $1,105 quote, you are asking the client to fund a conversation you did not have. Some will pay. They will not call you next time.
Enquiry, then a site visit if you need one, then a quote. Accepted quote becomes a work order. Work order becomes an invoice - deposit, progress, or final. Same job record the whole way. If a document cannot point at the one before it, you will lose the thread the first time someone asks what you agreed.
Only if the client has already agreed the price and you want payment now - a deposit, or the job is finished. An invoice with a due date, sent before anyone said yes, is a bill for work that does not exist yet. Most people ignore it, or argue later that they never approved the spend.
Send a quote. When they accept it, send a deposit invoice against that quote. The quote is still the offer. The deposit invoice is the first bill. Keep both on the same job so the remaining balance is obvious.
Invoice the agreed quote plus any variations the client approved. If you found extra chasing in the ceiling, that is a variation - not a quiet bump on the invoice. Surprises on the bill are how you lose the next job, even when the extra work was real.
It does not morph. You accept the quote, you do the work (or take a deposit), then you raise an invoice. Same job, new document, new number. If your software just reprints the quote with the word Invoice at the top and a due date, you still need the client to have agreed first.
Yes Foreman writes the quote from the brief, converts it to a work order when they say yes, and invoices the agreed figure plus any variation you logged on site.