Invoice vs receipt vs quote vs pro forma invoice
These documents look similar, and many small businesses use them interchangeably. They have different purposes, though, and sending the wrong one can confuse a client or cause problems with tax records. Here is what each one is for, in the order they usually appear in a sale.
Invoicing · Published 2026-10-07
Quote (or estimate): before the work
A quote tells a potential client how much a job will cost before they agree to it. It is an offer, not a request for payment, and nothing is owed yet.
An estimate is a looser version: a best guess that may change once the work starts. A quote is usually treated as a fixed price for the described scope. If you give an estimate, say so clearly and explain what could change the price.
A good quote lists the work, the price, what is not included, how long the price is valid (for example 30 days) and your payment terms. If the client accepts, the quote becomes the basis for your invoice.
Pro forma invoice: a preview of the invoice
A pro forma invoice looks like an invoice but is not a demand for payment and is not normally recorded as a sale in your accounts. It shows the buyer exactly what the final invoice will contain.
It is mainly used in three situations:
- International shipping, where customs needs to know the value of goods before the commercial invoice exists.
- Payment in advance, when a client's finance team needs an invoice-like document to release a deposit.
- Approval inside a large company, where a manager must sign off the cost before a purchase order is raised.
Always label it clearly as Pro Forma Invoice so nobody pays it twice or records it as a real invoice.
Invoice: the request for payment
An invoice is issued when the work is done or the goods are delivered (or at an agreed milestone). It is a formal request for payment and a record of the sale for both sides' accounts.
It needs a unique invoice number, the invoice date, your details and the client's details, a description of what was supplied, amounts, any tax, the total and the payment terms. If you are registered for VAT or GST, the rules for a valid tax invoice are stricter and are set by your tax authority.
Receipt: proof that payment was made
A receipt confirms that money has been received. It is issued after payment, either by you or automatically by a payment provider.
Receipts matter most to the buyer, who may need them for expense claims or tax deductions. A receipt should state the amount paid, the date, the payment method and what it was for, and ideally reference the invoice number it settles.
Some businesses mark the original invoice as Paid and send it again instead of a separate receipt. For small freelance work that is usually enough, but check what your client needs.
Quick comparison
- Quote: sent before work, an offer, no payment due.
- Pro forma invoice: sent before delivery or payment, a preview, no payment legally due.
- Invoice: sent after delivery, payment is due by the date shown.
- Receipt: sent after payment, proof that the invoice has been paid.
Which one should you send?
If the client has not agreed to the work yet, send a quote. If they have agreed but need something to process an advance payment, send a pro forma invoice. Once the work is delivered, send an invoice. When the money arrives, send a receipt if the client asks for one.
Zonlet's generator produces invoices. For a quote, you can use the same layout and add Quote and a validity date in the notes field, then create the real invoice once the client accepts.