A purchase order (PO) is the buyer's formal offer to purchase goods from a vendor: an itemized, numbered document listing what is ordered, at what price, delivered where and by when, and on what payment terms. Once the vendor accepts it, the PO becomes a binding contract.
Businesses use POs for a simple reason: the numbered paper trail. Every invoice, delivery, and payment ties back to one PO number, which keeps purchasing auditable and disputes short.
How a purchase order works
- The buyer sends the PO listing items, quantities, prices, delivery date, and payment terms
- The vendor accepts the order (in writing or by shipping the goods), forming a contract
- The vendor delivers and invoices, quoting the PO number
- The buyer matches the invoice against the PO and the delivery receipt, then pays on the agreed terms
That three-way match (PO, receipt, invoice) is the core control of business purchasing: it prevents paying for goods never ordered or never delivered.
Purchase order vs invoice vs sales order
| Document | Issued by | When | Purpose |
|---|---|---|---|
| Purchase order | Buyer | Before delivery | Offer to buy on stated terms |
| Sales order | Vendor | After PO acceptance | Vendor's confirmation of the order |
| Invoice | Vendor | After delivery | Request for payment |
A quote is not an order, and an invoice is not a contract. The PO is the document that fixes the terms before money and goods move, which is why it should carry your protective terms: inspection rights, rejection of non-conforming goods, and a bar on the vendor's conflicting fine print.
The protective terms built into this PO
This template includes the buyer-side protections that standard PO forms carry: time is of the essence for the delivery date, a right to inspect and reject defective or non-conforming goods at the vendor's expense, a warranty that the goods are new and conform to their description, and a clause stating that the vendor's conflicting terms do not apply unless accepted in writing. That last clause matters because vendors' acknowledgments often try to swap in their own terms.
Keep PO numbers sequential
Use a consistent numbering scheme (for example PO-2026-0001 and up). Sequential numbers make the three-way match trivial and are the first thing an accountant or auditor asks for.
Frequently asked questions
Is a purchase order legally binding?
The PO itself is an offer. It becomes a binding contract when the vendor accepts it, either by confirming in writing or by shipping the goods. After acceptance, both sides are bound by the PO's terms.
What is the difference between a PO and a contract?
A PO is a contract once accepted, optimized for goods: items, quantities, prices, delivery. For complex ongoing supply relationships, companies often sign a master agreement and then issue POs under it for each order.
Can I cancel a purchase order?
Before the vendor accepts, yes: an offer can be withdrawn. After acceptance, cancellation needs the vendor's agreement, except where the PO itself allows it, such as this template's right to cancel items not delivered by the required date.
What if the delivered goods are defective or wrong?
Under this PO, you may reject damaged, defective, or non-conforming goods and return them at the vendor's expense for replacement, credit, or refund. Inspect promptly on delivery and document problems with photos and a written notice.
Do purchase orders include sales tax?
This template states the total excludes taxes and shipping unless agreed otherwise. Whether sales tax applies depends on the goods, the states involved, and any resale exemption; provide your resale certificate to the vendor if you are buying for resale.