A purchase agreement is a binding contract that sets out the terms of a sale, including price, what is being sold, and the obligations of buyer and seller.

A purchase agreement is a legally binding contract that sets out the terms under which a buyer purchases goods, assets, or property from a seller. It records what is being sold, the price, and the rights and obligations of each party.
Quick answer: a purchase agreement is the document that makes a sale enforceable. It turns a verbal "yes" into defined, binding terms both sides can rely on.
A purchase order is a buyer's request to order goods at a stated price. A purchase agreement is a fuller contract covering terms, warranties, and remedies. They are related but not identical, and a purchase order can itself become binding in certain conditions. We cover this in is a purchase order a contract?
In procurement, the purchase agreement is the contract stage of the buying cycle, after sourcing and negotiation. Managing these agreements at scale, with their renewal dates and pricing terms, is far easier when they are treated as connected data rather than static files. For the bigger picture, see our guide to procurement and to types of contracts.
Is a purchase agreement legally binding?
Yes. Once signed by both parties and supported by the essential elements of a contract, a purchase agreement is enforceable.
What is the difference between a purchase agreement and a purchase contract?
The terms are largely interchangeable. Both describe a binding agreement that sets out the terms of a sale, though purchase agreement is the more common phrasing.
Who prepares the purchase agreement?
Either party can draft it, but the seller or the party with more bargaining power often provides the first version. Both sides should review the terms before signing.