PO number
A PO number is the reference a buyer assigns to an approved purchase order. Sellers place it on related quotes, deliveries and invoices so the buyer can match the charge to its internal authorization. The PO number belongs to the customer's purchasing process and is different from the seller's invoice number.
Why this matters when you invoice
Including the correct PO number can help the customer's accounts-payable team route and approve an invoice without asking the seller to resubmit it.
Where it appears on an invoice
Place it in a clearly labelled purchase-order or customer-reference field. Keep the seller's invoice number separate and copy the PO exactly as supplied by the customer.
PO number example
A customer approves purchase order PO-78421 for design services. The designer issues invoice IC-1042 and enters PO-78421 in the PO-number field so the customer can match both records.
Common mistakes
- Using the PO number as the seller's invoice number.
- Inventing a PO number when the customer did not provide one.
- Copying a project name instead of the approved order reference.
Put it into practice
Use the matching InvoiceCraftly resource to apply this concept, then review the result in the context of your invoice and agreement.
This page explains common invoicing usage. Your agreement and applicable local rules determine what applies to a transaction.
Frequently asked questions
Does every invoice need a PO number?
No. It is needed when the buyer's process or agreement requires one.
Who creates the PO number?
The buyer normally creates it when authorizing a purchase. The seller then reproduces that reference on related documents.