What Information Should an Invoice Include?

A proforma invoice can look very similar to a normal invoice, which is why the two documents are often confused. Both may show seller details, customer details, products or services, quantities, prices, taxes, and a total. The important difference is their purpose.

A proforma invoice is generally a preliminary document showing what a transaction is expected to cost. A normal invoice is a formal request for payment after the agreed billing event.

What is a proforma invoice?

A proforma invoice is an advance or preliminary statement of a proposed transaction. Businesses may use it before goods are shipped, before an international shipment is cleared, before a customer makes an advance payment, or while final commercial details are still being confirmed.

It should be clearly marked as Proforma Invoice so the customer does not mistake it for the final billing document.

What is a regular invoice?

A regular invoice is a document issued by the seller to request payment. It normally has a unique invoice number, invoice date, due date, seller and buyer details, line items, tax, and total amount due.

For a practical checklist, see what information an invoice should include.

Proforma invoice vs invoice comparison

Feature	Proforma Invoice	Invoice
Purpose	Preliminary transaction information	Request payment
Timing	Before final billing	At agreed billing point
Can details change?	Often yes	Should reflect final billed transaction
Label	Proforma Invoice	Invoice

Why businesses use proforma invoices

To show the expected cost

A customer may need detailed pricing before approving a purchase. The proforma document can show quantities, unit prices, shipping costs, taxes, and the expected total.

To support advance payment

Some businesses use a proforma invoice when requesting payment before goods are dispatched. The final invoice is then issued according to the business’s accounting and legal requirements.

For international trade

Proforma invoices are often used to provide shipment values and product information before the final commercial invoice is available. Exact customs requirements vary, so follow the relevant rules.

Is a proforma invoice the same as a quotation?

They can serve similar purposes because both may be sent before the final invoice, but they are not always used in the same way. A quotation usually presents an offer: what the seller will provide, the price, validity period, and terms.

If you simply need to send pricing before the sale, a quotation may be clearer. Use the Quotation Generator or read how to create a professional quotation.

Does a proforma invoice need an invoice number?

Businesses often use a separate numbering system or reference for proforma documents so they are not confused with final invoices. The exact approach depends on your accounting process and local requirements.

The key is to avoid making a preliminary document look like a final sales invoice when it is not.

Can the final invoice be different?

Yes, when legitimate details change before final billing. Final quantities, freight, approved discounts, taxes, or other charges may differ from the preliminary figures.

If the final invoice changes significantly, make sure the customer understands the reason.

Should a proforma say “Not a Tax Invoice”?

In some jurisdictions or business contexts, companies clearly state that a proforma invoice is not a tax invoice. Invoice and tax rules vary, so follow the requirements that apply to your location and transaction.

Do not assume the document name has the same legal or tax treatment everywhere.

Example transaction

A supplier agrees to sell machinery for $12,000 plus shipping. The customer needs a detailed document for internal approval. The supplier issues a proforma invoice showing the equipment, estimated freight, delivery terms, and expected total.

After final shipping cost and quantities are confirmed, the supplier issues the normal invoice for the amount actually due.

When should you use a quotation instead?

Use a quotation when you are presenting an offer before the customer has committed. It is useful for services, projects, repairs, consulting, design, construction, and similar work where the client needs to approve the price first.

Our invoice vs quotation guide explains how those documents fit into the sales process.

Ready to issue the final invoice?

Create a professional invoice with your business details, customer information, line items, taxes, discounts, and total.

Open Invoice Generator

Common mistakes

• Failing to label a proforma clearly.
• Treating it as the final accounting invoice without checking requirements.
• Using the same final invoice number for multiple preliminary versions.
• Not issuing the final invoice when required.
• Changing totals without explaining why.

Frequently asked questions

Is a proforma invoice a request for payment?

It may be used in connection with advance payment, but it is generally preliminary rather than the final sales invoice.

Can I use a quotation instead?

Often yes when the main goal is to communicate pricing before the customer agrees to buy.

Can a proforma invoice change?

Yes. It is often prepared before final quantities or charges are confirmed.

Final thoughts

A proforma invoice looks like an invoice but normally comes earlier in the transaction and communicates expected details rather than final billing. A regular invoice is the seller’s formal request for payment. Label documents clearly, keep preliminary and final records separate, and follow the accounting and tax rules that apply to your business.