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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 — and the usual result is goods held at customs.

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 transaction value — trial samples, replacement items, goods sent for testing — some exporters use a proforma to give customs a declared value for clearance. In practice a marked-up commercial invoice is usually the better choice; see the samples section below.
• 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 and creates a legal obligation to pay. (It does not itself create VAT due on an export — UK exports of goods are zero-rated — but it is the record HMRC expects behind the zero-rating, and the document your buyer's tax authority works from.) 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 statement on origin if claiming preferential duty under the TCA 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

Getting samples wrong. A common misconception is that the document label decides whether the recipient gets charged. It doesn't: import charges follow the declared customs value and any samples relief available, not whether the paperwork says "proforma" or "commercial invoice". Nor will customs accept a genuinely zero value — even free goods must be declared at a realistic value. The standard, carrier-accepted practice is a commercial invoice marked "Samples — no commercial value; value for customs purposes only", showing a realistic nominal value. That wording creates no sale and no VAT liability, and gives customs a value to clear the goods against.

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, and temporary exports. For samples, use a commercial invoice marked as described above.

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, 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.