What is a purchase order?
A purchase order (PO) is a document a buyer sends a supplier listing the items, quantities, agreed prices and delivery terms of a purchase. Once the supplier accepts it, it becomes a binding agreement — and the PO number becomes the reference that ties together the order, the shipment and the invoice.
What's the difference between a purchase order and an invoice?
Direction. The buyer issues the PO before goods ship (“this is what we're ordering”); the supplier issues the invoice after (“this is what you owe”). A clean paper trail matches invoice → PO number → packing slip, which is exactly why every PO needs a unique number.
Is a purchase order legally binding?
Generally yes, once accepted by the supplier — a PO is an offer to buy that becomes a contract on acceptance. That's why quantities, unit prices and terms should be exact before you send it.
How should I number purchase orders?
A simple ascending sequence (PO-1001, PO-1002…) works for most small businesses. Some add a year or project prefix (PO-2026-014). Whatever the scheme, never reuse a number — traceability is the entire job of a PO.
Is this purchase order generator free?
Yes — create and download unlimited POs as PDFs, no sign-up. Data is stored only in your own browser.