Offer and acceptance analysis is a traditional approach in contract law used to determine whether an agreement exists between two parties. As a contract is an agreement, an offer is an indication by one person (the "offeror") to another (the "offeree") of the offeror's willingness to enter into a contract on certain terms without further negotiations. A contract is said to come into existence when acceptance of an offer (agreement to the terms in it) has been communicated to the offeror by the offeree.
The offer and acceptance formula, developed in the 19th century, identifies a moment of formation when the parties are of one mind. This classical approach to contract formation has been weakened by developments in the law of estoppel, misleading conduct, misrepresentation and unjust enrichment.