Invoice vs quotation: which document, and when
Send the wrong one and you either ask for money you have not earned or give away work you never priced. The difference is about timing and obligation, not formatting.
The short answer
A quotation comes first. It is an offer: this is what I will do, this is what it costs, and this is how long the price holds. The customer can accept it or walk away, and nobody owes anybody anything until they accept.
An invoice comes last. It is a demand for payment for work already delivered or goods already supplied. It creates a debt, it goes into both sides' accounts, and in most tax systems it is the document the tax is actually reported on.
Side by side
| Quotation | Invoice | |
|---|---|---|
| When | Before the work | After the work |
| What it does | Offers a price | Asks for payment |
| Creates a debt | No | Yes |
| Key date | Valid until | Due date |
| Customer can decline | Yes, freely | No — it is already owed |
| Usually reported for tax | No | Yes |
The fields that are genuinely different
Most of both documents is the same: who is selling, who is buying, the line items, the quantities, the unit prices, the per-line discount and tax, and the totals. The differences are few and they are the ones that matter.
On a quotation and not on an invoice
- Valid until — the date the price stops being an offer. Without it a quote is open indefinitely, which is a liability when your own costs move.
- A reference — the customer's enquiry or RFQ number, so their buyer can match your offer to their request.
- Terms and conditions — what the price assumes, what is excluded, and what happens if the scope changes.
- A status that can be rejected — a quotation is draft, sent, accepted, rejected or expired. An invoice has no "rejected".
On an invoice and not on a quotation
- A due date — and, with it, the payment term. See how to write payment terms.
- A date of supply — when the goods or service were actually delivered, which is not always the day the invoice was raised.
- Payment instructions and bank details — a request for money that does not say where to send it will be paid late.
- Payment method — cash or credit, which some tax regimes require to be stated on the face of the document.
- Both parties' tax and registration numbers — a business buyer's accounts department will check them.
Quotation, estimate, proposal, RFQ, pro forma
Four of these get used interchangeably and should not be. The distinction is how binding the number is.
| Document | What it commits you to |
|---|---|
| Estimate | An informed guess. The final figure is expected to move. |
| Quotation | A fixed price for a defined scope, until the valid-until date. |
| Proposal | The approach and the price. Sells the method as well as the number. |
| RFQ | Nothing — it is the buyer asking you for a quotation. |
| Pro forma invoice | A priced document for payment in advance. Not a tax invoice. |
Turning an accepted quote into an invoice
The two generators are separate tools and there is no one-click conversion between them. What they share is the business profile — your letterhead, logo, tax number and default currency — so the second document does not mean retyping the first one's header.
Build the quotation
Open the Quotation Generator, add the lines, set a valid-until date, and download or send the PDF.
Get the acceptance in writing
An email saying "go ahead" against a quotation number is enough, and it is what you will want if the scope is argued about later.
Raise the invoice after delivery
Open the Invoice Generator and copy the accepted lines across. Quote the quotation number in the invoice notes so the customer's accounts team can match the two.
Set the due date from the terms you agreed
Not from habit. If the quotation said 30 days, the invoice says 30 days.
What these tools will not do
- No automatic conversion from an accepted quotation into an invoice. The lines are copied by hand.
- Payment tracking on an invoice is held by the browser, not the account. Marking an invoice paid is remembered on the device you did it on. Clear the browser data or move to another machine and that state is gone, even though the invoice itself is saved.
- No chasing. Nothing sends a reminder when a due date passes.
- No accounting ledger. These produce documents; they are not a bookkeeping system, and they do not file anything with anyone.
Frequently asked questions
- Can a customer refuse to pay an invoice because they never saw a quotation?
- They can certainly argue it, and the argument is much stronger when there is no accepted quotation to point at. A written acceptance against a numbered quotation is what closes that door.
- How long should a quotation stay valid?
- Long enough for the customer to decide and short enough that your costs have not moved. Thirty days is the common default; on anything where materials or exchange rates matter, shorter is safer. The field is yours to set.
- Can I invoice before doing the work?
- For a deposit or an advance, yes — though in several tax systems the correct document for a request for prepayment is a pro forma invoice, with the tax invoice following the supply. Check what your own rules require.
- Do both documents need a number?
- Yes, and it should be sequential. When you are signed in, numbering is assigned by the system rather than typed, which is what stops two documents ending up with the same number.
- Can I issue these in Arabic?
- An invoice prints in English or in English with Arabic beneath it. A quotation adds a third option — Arabic only — because a purely local customer often has no use for the English column.
The tools behind this
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About the author
Naeem Ahmed builds and runs BuzPulse. These guides describe tools he has built, and they describe how those tools actually behave — including where they stop.
Corrections and questions: nsglobal6@gmail.com
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