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Export Documents

A proforma invoice and a commercial invoice look nearly identical on paper. Both list the goods, the prices, the parties involved, and the shipment details. But they serve entirely different legal and commercial purposes — and using one when you should be using the other is one of the most common document errors in international trade, capable of causing customs clearance delays, VAT complications, and contractual disputes.

What a Proforma Invoice Is

A proforma invoice is a preliminary document — a statement of intent rather than a record of a completed transaction. It describes what goods will be supplied, at what price, under what terms, but it does not record a sale that has actually taken place. It creates no legal obligation to pay and no VAT liability.

Proforma invoices are used in several specific situations:

• Pre-payment requests: requesting payment from a buyer before dispatching goods, particularly for new customers or large orders. The buyer pays against the proforma; the commercial invoice follows with or after the goods.
• Samples and free-of-charge goods: when goods have no commercial value in the transaction — trial samples, replacement items, goods sent for testing — a proforma invoice is used to give customs a declared value for clearance purposes without implying a commercial sale.
• Trade show and temporary export goods: goods exported temporarily for display or demonstration, with the intention of re-importing them, are often accompanied by a proforma rather than a commercial invoice.
• Quotations: some exporters issue proforma invoices as a formal quote to a potential buyer, showing the exact terms under which they would supply the goods.

What a Commercial Invoice Is

A commercial invoice is the definitive record of a completed commercial transaction. It documents a sale that has taken place or is taking place, creates a legal obligation to pay, and generates a VAT liability (for VAT-registered parties). It is the primary document used by customs authorities worldwide to assess the correct duty rate, determine customs value, and verify compliance with import regulations.

Every commercial export of goods requires a commercial invoice. See the full commercial invoice guide for the complete list of fields that must appear on a UK export commercial invoice — including goods description, HS code, country of origin, Incoterms, declared value, and the TCA supplier's declaration if claiming preferential duty for EU buyers.

Why Using the Wrong One Causes Problems

Submitting a proforma as a customs invoice. This is the most common mistake. A UK seller uses their proforma invoice (perhaps because it was already prepared for the buyer) as the customs document accompanying the shipment. Customs authorities in the destination country see an invoice labelled "proforma" and know it is not a legally binding transaction record. They may:

• Hold the shipment and request the correct commercial invoice before releasing the goods
• Query the customs value, since proforma values may not reflect the final agreed price
• Assess duty on an estimated value, which may be higher or lower than the actual transaction value

Using a commercial invoice for genuinely free samples. If you send a sample with no commercial value and attach a commercial invoice, you have technically documented a sale with a VAT liability and an obligation to pay. The recipient may be charged duty and import VAT on the sample — precisely what you were trying to avoid. For genuine samples, a proforma with a nominal or zero value (and a clear statement that the goods are samples of no commercial value) is the appropriate document.

Proforma used for pre-payment, commercial invoice never issued. A business requests payment via proforma and ships the goods, but never issues the formal commercial invoice. From the buyer's perspective, there is no VAT invoice to support an input VAT reclaim. From HMRC's perspective, the VAT chain is incomplete. Always issue a commercial invoice once the goods ship, even if the proforma was used for the initial payment request.

The Practical Rule

Use a proforma for: quotes, pre-payment requests, samples, temporary exports, and goods with no commercial transaction value.

Use a commercial invoice for: every shipment where goods are being permanently sold and transferred to a buyer. If in doubt about which applies to a specific situation, the question to ask is: "Has a sale taken place?" If yes, use a commercial invoice. If no, use a proforma.

ClearDocs generates commercial invoices — the definitive transaction document — not proformas. For every standard commercial export, this is the correct document to produce. The practical guide to which export documents you need covers the full document set for each export scenario.