17 October 2026 · 7 min read
Proforma invoice vs invoice: what actually differs
The two documents can look identical — same logo, same line items, same total. The difference is legal, and it is the difference between a document that asks for money and one that only describes what money would buy. Get the distinction wrong and you either record revenue that has not happened or issue a tax invoice before a supply exists.
One document describes a sale; the other concludes it
An invoice is a demand for payment for goods or services that have been supplied. A proforma invoice is a preview of that demand, sent before the supply happens. It is the difference between a menu and a bill: the menu tells you what the meal will cost, and nobody owes the restaurant until they have eaten.
That distinction drives everything else. A proforma is not a tax document, it does not create a tax point, it is not recorded as revenue, and it cannot be used by the buyer to reclaim VAT. It exists to confirm price, quantity, delivery terms and payment instructions before either side commits.
The confusion is understandable, because the fields are almost the same. If you have already read what an invoice should include, you have seen the list: seller details, buyer details, description, quantity, unit price, totals, terms. A proforma carries nearly all of it, which is exactly why it must be labelled clearly and numbered in its own series.
The differences that matter
| Point | Proforma invoice | Commercial / tax invoice |
|---|---|---|
| Purpose | Confirm what a sale would cost before it happens | Request payment for a supply that has happened |
| Legal weight | A quotation with invoice formatting — not a demand for payment | A demand for payment; the basis of the accounting entry |
| Tax | No tax point; tax is shown for information only | Creates the tax point; VAT or GST is charged and reclaimable |
| Accounting | Not recorded as revenue — no debtor is created | Recorded as revenue and as a receivable |
| Numbering | Its own series, e.g. PRO-2026-0007 | The invoice series, e.g. INV-2026-0042 |
| What follows it | An invoice, once goods ship or work is delivered | A receipt, once payment arrives |
The tax row is where mistakes become expensive. A registered vendor may only charge tax on a tax invoice, and a tax invoice may only be issued for a supply that has taken place. Putting a VAT number and 15% VAT on a proforma, then filing the output tax before the work is delivered, moves a tax liability into the wrong period — and the buyer cannot reclaim tax on a document that is not a valid tax invoice.
When a proforma invoice is the right document
- Advance payment or deposit. The client needs something official to raise a purchase order or release funds. A proforma gives them the amount, the bank details and a reference without pretending the work has been done.
- Cross-border shipping. Customs and freight agents routinely ask for a proforma to value goods before export. It describes the consignment; the commercial invoice is issued at dispatch.
- Approval inside a large organisation. Procurement wants a document to attach to a requisition. A proforma moves that process along while the invoice stays unissued.
- Price confirmation for a complex job. When quantities may change, a proforma fixes the unit prices and the terms before the final document is produced.
Converting it without breaking the trail
- Issue the final invoice under the invoice series, not the proforma number, and quote the proforma reference in the notes. The client can then match the two documents without guessing.
- Keep the line items, quantities and prices identical unless something genuinely changed. If it did change, show the difference rather than quietly issuing a new total.
- State the tax treatment on the invoice itself — rate, amount and registration number — now that a tax point exists.
- Mark the proforma as converted in your own records, so nobody re-sends it as if it were still awaiting payment.
- If a deposit was paid against the proforma, deduct it as a separate line and show the balance due, rather than invoicing the full amount twice.
The reference between the two documents is what makes reconciliation possible. The same discipline applies to quotes that become invoices — the final document should always name the document it replaces or fulfils.
The mistakes that cost money
| Mistake | What goes wrong | The fix |
|---|---|---|
| Calling it an "invoice" without qualification | The client files it as a payable and expects to be chased; your accounts show revenue that does not exist | Label it PROFORMA INVOICE, and add "not a tax invoice — no payment due until dispatch" |
| Charging VAT on the proforma | Output tax lands in the wrong period; the buyer's reclaim is invalid | Show tax as an estimate only, or omit it until the tax point exists |
| Reusing the invoice number | Two documents share one identity, and the series gains an unexplainable duplicate | Use a separate PRO- series, and carry the reference into the final invoice |
| No expiry | A price confirmed in January is treated as valid in December | Add "valid until" and a payment window to the proforma |
| Sending a proforma when payment is already due | The client waits for a "real" invoice before paying, and the due date slips | Issue the tax invoice as soon as the supply happens |
Frequently asked questions
Is a proforma invoice legally binding?
It is generally treated as a quotation or an offer, not a demand for payment. Whether it binds either party depends on the wording and the contract around it. A proforma that says "payment on receipt of this document" is really an advance-payment request and should say so explicitly.
Can a client claim VAT on a proforma invoice?
No. VAT is only reclaimable on a valid tax invoice, and a proforma is not one. If you show tax on a proforma, label it clearly as an estimate and issue a proper tax invoice once the supply happens.
Should a proforma invoice use the same number as the final invoice?
No. Use a separate prefix and counter — PRO-2026-0007 — and quote that reference on the final invoice. Sharing a number creates two documents claiming to be the same thing, which is precisely the ambiguity a numbering series exists to prevent.
Do I need to send a proforma invoice before every invoice?
No. It is optional and mostly useful when a client needs a document before paying, importing or approving the spend. For a straightforward job with an agreed price, send the invoice when the work is delivered.
How does a proforma differ from a quote?
A quote is an offer to do work at a price; a proforma is a preview of the invoice that would follow. In practice they overlap, and many businesses use a quote until the client accepts and a proforma once they need to pay a deposit.
What happens if the final invoice differs from the proforma?
Explain the difference on the invoice — extra days, changed quantities, a different tax rate. The client approved one number and is being asked for another, so the document has to show why. Keep the proforma reference in the notes.
Sources
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When the work is delivered, the document should stop being a preview. FreeInvoices keeps a separate series for quotes and invoices, carries the reference across, and produces a print-ready PDF with the tax lines already in the right place.
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