Proforma Invoice vs Invoice: Differences and When to Use Each

A client asks you to "send an invoice so I can get the purchase approved" — but the work has not started, nothing has been delivered, and you are not ready to book the sale. Send a real invoice now and you have created a tax document for a transaction that may never happen. Send nothing and the deal stalls.

That is exactly the gap a proforma invoice fills. It looks like an invoice, it carries the same numbers, and it gives your customer something official to act on — but it is not an accounting document and it does not commit either side to anything. This guide explains what separates a proforma from a commercial invoice, when each one is the right tool, what to put on a proforma, and the mistakes that cause real problems with accountants and tax authorities.

What is a proforma invoice?

A proforma invoice is a preliminary document that states, in invoice format, what you intend to charge: the goods or services, quantities, unit prices, applicable taxes and the total the buyer should expect to pay. The Latin pro forma means "as a matter of form" — the form of an invoice, without its legal substance.

Three characteristics define it:

• It is not a tax document. A proforma does not record a sale, does not go into your sales ledger, and does not create a VAT liability for you or a deductible input VAT for your customer.
• It is a commitment to price, not a demand for payment. It tells the buyer what the transaction will cost if they proceed.
• It is provisional. Quantities, delivery dates or specifications can still change before the final invoice is issued.

In practice, a proforma is a quote wearing an invoice's clothes. It exists because many buyers — especially corporate purchasing departments, customs officers and banks — need a document that looks and reads like an invoice before they will release a purchase order, clear a shipment or approve a transfer.

What is a commercial invoice?

A commercial invoice — the ordinary, final invoice — is the legal record of a completed transaction. It is issued when goods have been delivered or services rendered (or when an advance payment is received), and it triggers real consequences: it enters your bookkeeping, it forms part of your VAT return, it starts the payment clock, and it is the document your client needs to deduct the expense and, where applicable, reclaim input VAT.

Because it is a legal document, its content is regulated. Most jurisdictions require a unique sequential number, issue date, full identification of both parties including tax IDs, a description of what was supplied, the taxable base, the tax rate and amount, and the total payable. The exact list varies by country — if you invoice in Spain, our breakdown of the legal invoice requirements in Spain covers what every factura must include, and for the tax treatment itself see our guide to IVA rates, exemptions and how to apply VAT on your invoices. Always confirm the current rules with your national tax authority before changing how you invoice.

Proforma invoice vs invoice: the key differences

The last row matters more than it looks. A document that omits the word "proforma" but carries a number from your live invoice series can be treated as a real invoice by your client's accountant — and that is how phantom revenue ends up in someone's books.

When to use a proforma invoice

Getting a purchase approved

Larger clients often cannot raise a purchase order from a quote; their procurement system wants an invoice-shaped document with tax figures. A proforma satisfies that requirement without you recognising revenue for an order that has not been confirmed.

Requesting payment in advance

For new clients, custom work or large material costs, asking for a deposit is reasonable. Send a proforma for the advance amount, and issue the real invoice once the payment lands or the work is delivered, according to the rules that apply in your country. This is one of the most effective ways to shorten your cash cycle — see our tips to get paid faster for the other levers.

International shipping and customs

When goods cross a border before a final invoice exists, customs authorities and freight forwarders typically ask for a proforma to value the shipment and calculate duties. It should state the currency, incoterms, country of origin, weight and HS codes where relevant. If you bill across currencies, our guide to invoicing international clients with multi-currency support explains how to handle exchange rates cleanly.

Confirming a negotiated deal

After a quote has been discussed and adjusted, a proforma restates the final agreed terms in a format both sides recognise — useful when the accepted quote and the eventual invoice may be weeks apart.

When you must issue a real invoice instead

A proforma is never a substitute for the final document. Issue a commercial invoice when:

• the goods have been delivered or the service completed;
• you have received payment, including a deposit, where your local rules require an invoice for advances;
• your client needs the document to deduct the expense or reclaim input VAT;
• you need an enforceable claim before chasing a late payment;
• the amount has to appear in your periodic VAT or income tax filings.

If you discover an error after issuing a real invoice, do not delete it and do not overwrite it. Issue a corrective invoice or credit note that references the original — that audit trail is what tax inspectors look for.

What to include on a proforma invoice

There is no universal legal template, precisely because a proforma is not a regulated document. But a useful one mirrors the final invoice closely enough that nothing surprises the buyer later:

1. The words "Proforma invoice" in the header, unmistakably.
2. A reference number from a separate series (PRO-2026-014, not INV-2026-014).
3. Issue date and a validity date — prices should not stay open forever.
4. Full details of both parties, including tax identification numbers.
5. Line-by-line description, quantity, unit price and discounts.
6. Taxable base, the tax rate you expect to apply, and the estimated total.
7. Payment terms, accepted methods and bank details.
8. For shipments: currency, incoterms, origin, weight and tariff codes.
9. A short disclaimer: this document is not a valid invoice for tax purposes.

Common mistakes to avoid

• Using your official numbering. Pulling a number out of the live invoice sequence creates a gap you will have to explain later. Keep the series separate.
• Recording it as revenue. A proforma is not income. It should not appear in your sales ledger or your VAT return.
• Never converting it. The most expensive mistake is delivering the work, getting paid against a proforma, and forgetting to issue the real invoice. Your client cannot deduct the expense, and your books do not reflect the sale.
• Leaving prices open-ended. Without a validity date, a proforma issued months ago can be waved back at you at outdated prices.
• Confusing it with a quote. A quote invites negotiation; a proforma states terms that are essentially settled. Sending a proforma too early in the conversation reads as presumptuous.

From proforma to paid: making it one workflow

The practical difficulty is not understanding the difference — it is keeping the two documents in sync. Retyping a proforma into a final invoice is where wrong amounts, missing lines and duplicated numbers creep in.

The cleaner approach is to build the document once and convert it. In Facturi you can prepare the figures as a quote or proforma, send it for approval, and turn the approved document into a numbered invoice in one click — the same workflow described in our guide to creating quotes and converting them into invoices. Numbering series stay separate, the final invoice inherits every line, and nothing is retyped. If you are still assembling documents by hand, our walkthrough on creating a professional invoice online in under five minutes is a good place to start.

Try Facturi free and send your first proforma — and the invoice it becomes — today.

Frequently asked questions

Is a proforma invoice legally binding?

Not as an invoice. It creates no enforceable debt and no tax obligation. It can, however, form part of the commercial correspondence that evidences an agreement, so treat the terms on it as terms you are prepared to honour.

Can a client pay against a proforma invoice?

Yes, and many do — that is common practice for advance payments. Once the money arrives, issue the corresponding commercial invoice in line with the rules that apply where you operate.

Can I deduct VAT from a proforma invoice I received?

No. Input VAT is deductible only on the basis of a valid invoice that meets your country's content requirements. If a supplier only ever sends you a proforma, ask for the final invoice.

What is the difference between a proforma invoice and a quote?

Function and timing. A quote is an offer opening a negotiation; a proforma restates near-final terms in invoice format so the buyer can act — approve internally, release funds or clear customs.

Does a proforma invoice need a sequential number?

It does not need one legally, but give it a reference from its own separate series anyway. It keeps your records traceable without ever touching the official invoice sequence.

The short version

Use a proforma when you need to show a client exactly what something will cost before anything is delivered, paid or booked. Use a commercial invoice the moment the transaction becomes real — because that is the only document that counts for your accounts, your client's deduction and your tax filings. Keep the two in separate numbering series, always convert one into the other, and check your national tax authority's guidance whenever the rules on invoice content or timing are at stake.