The short version
An estimate is a view, a quote is a fixed price, a work order is an instruction, an invoice is a request for payment and a receipt is proof it arrived. Only the quote and the invoice commit you to a figure. Sending the wrong one is how a guide price becomes a price you are held to.
The five, in the order they go out
| Document | What it says | When it goes out | Commits you? |
|---|---|---|---|
| Estimate | Your considered view of the cost, with ranges and assumptions written down | Before the scope is firm | No |
| Quote | A fixed price the client can accept as it stands, valid until a date you set | Once you know the work | Yes, once accepted |
| Work order | The instruction to carry the work out: site, schedule, tasks, sign-off | After the go-ahead | Internally |
| Invoice | The request for payment, with a due date and how to pay | After the work, or at an agreed stage | Yes |
| Receipt | Proof the money arrived, and what it was for | After payment | No |
Estimate against quote: the one that costs people money
This is the pair that causes the arguments. The words are used interchangeably in conversation and they are not interchangeable on paper.
A quote is an offer. You are saying: this work, this price, and if you accept it that is what it costs. Once the client accepts, you are held to the figure, which is why a quote needs a valid-until date and a written list of what is included.
An estimate is your best view of a cost you cannot yet pin down. The figures are allowed to move, and what makes it honest rather than vague is that the reasons they might move are written on the document: the allowances, the ranges and the assumptions.
Say which it is, at the top. The title on the page is the whole difference. A document headed Estimate with a single tidy total reads exactly like a quote to somebody who is not thinking about it.
Invoice against bill against receipt
Invoice and bill are the same document seen from two ends. You send an invoice; the person receiving it puts it on the pile of bills. If a client asks for a bill, send an invoice and change the title.
A receipt is a different thing and the difference is a date. An invoice asks for money on a future date. A receipt records that money arrived on a past one, and carries three things an invoice cannot: the date of payment, the method, and the amount actually received.
- An invoice needs a number, an issue date, a due date, the work, the total and how to pay.
- A receipt needs a number, the date the money arrived, the method, what it was for, and which invoice it settles.
- Both need your details and the client's, because both end up in somebody's records.
Where the work order fits
A work order is the only one of the five that is not about money. It is the instruction: what to do, at which address, in which window, with which parts, and who signs to say it was done. On a one-person job it lives in your head. On any job where somebody else turns up, it has to be on paper or it gets done wrong.
The useful habit is to keep the customer's description of the problem separate from what you find. The two disagreeing is the most valuable line on the sheet, and it is the line that settles the argument later.
Turning one into the next without retyping
Each document already contains most of the next one. An accepted quote holds the client, the lines, the quantities and the rates; the invoice is the same page with a different title, an issue date, a due date and terms.
- Estimate to quote. Firm up the allowances, remove the ranges, add a valid-until date and a signature line.
- Quote to work order. Keep the tasks, drop the prices if the crew does not need them, add the site, the window and the sign-off.
- Work order to invoice. The parts and hours you filled in on site are the invoice lines. Change the title, set the dates and the terms.
- Invoice to receipt. Record the date the money arrived and the method, and mark it paid.
Because every design here exists in all five studios, doing this keeps one look across the whole job: the estimate, the quote, the work order, the invoice and the receipt.
The three that are not on the list
- Proforma invoice. An invoice sent before the work is committed, usually so the client can raise a purchase order. Not a demand for payment and not a sale yet.
- Credit note. An invoice in reverse. It corrects or cancels one you have already sent, and it is what you raise instead of deleting an invoice or reusing its number.
- Statement. A list of every invoice outstanding on an account, sent monthly. It is a reminder, not a demand, and it does not replace the invoices it lists.
The other words clients use for the same five documents
Half of the confusion is vocabulary. The same document goes by different names by country, by trade and by the size of the client, and a client asking for a proposal usually wants a quote.
| What you would call it | What a client might ask for | What they want |
|---|---|---|
| Quote | Quotation, bid, proposal, tender, offer | A fixed price they can accept |
| Estimate | Ballpark, rough price, indication, budget price | A number to plan around, not to hold you to |
| Work order | Job sheet, job card, service order, docket | Written authority to start |
| Invoice | Bill, statement, request for payment | The amount owed, and how to pay it |
| Receipt | Sales receipt, proof of payment, paid invoice | Evidence the money arrived |
A statement is the one genuine exception. It is not another word for an invoice: it lists every invoice on an account and what is still outstanding, which is why sending one instead of an invoice gets you nothing paid.
When a client asks for the wrong one
- They ask for an invoice before the work. They usually mean a deposit invoice or a proforma. Send the one that matches what they are paying for and say which it is on the document.
- They ask for a quote and describe a job nobody could price yet. Send an estimate, labeled as one, with what would change it. A quote you cannot stand behind becomes an argument at the end.
- They ask for a receipt for an unpaid invoice. They generally want the invoice for their own records. Send the invoice; keep the receipt for after the money arrives.
- Their accounts team asks for a copy invoice. Send the same document with the same number, not a new one. A second number for one job is how an invoice gets paid twice or not at all.
The tools for this
Common questions
What is the difference between an invoice and a bill?
Nothing except who is speaking. You send an invoice; the person who receives it calls it a bill. Bill format and invoice format describe the same document.
What is the difference between a quote and an estimate?
A quote is a fixed price the client can accept as it stands. An estimate is your considered view of the cost before the scope is firm, with the ranges and assumptions written down. Same layout, different promise.
Is an invoice a receipt?
No. An invoice asks for money; a receipt proves it arrived. The receipt carries the date the payment was made, the method and the amount, none of which an invoice can know.
Do I need a work order if I already have a quote?
On a job with a crew, yes. The quote is the price the client agreed to; the work order is the instruction that tells whoever turns up what to do, where, when, and who signs it off.
Can one document be both an invoice and a receipt?
It can, if the money arrived at the same moment. Mark it paid, note the method and the date, and it does both jobs. Anything paid later needs a receipt of its own.
What is a proforma invoice?
An invoice sent before the work is committed, so the client can raise a purchase order or arrange payment. It is not a demand for payment and does not go in your sales figures until it becomes a real invoice.
Is a bill the same as an invoice?
In everyday use, yes. Bill is what the person receiving it calls the document, invoice is what the person sending it calls the same document. The word on the page should be invoice, because that is the word an accounts system is looking for.
Can a quote become an invoice?
Yes, and it should: the same lines, the same prices, the same wording, so the client can see nothing changed. The quote to invoice guide walks through the conversion and what has to change.