What You'll Learn

  • Who may accept
  • Promise versus performance
  • Methods and notice
  • Silence and conduct
  • Mailbox rule and counteroffers

Educational information only; not legal advice. This article is a general study aid and should be checked against current authority and course materials.

1. Only the Intended Offeree May Accept

The power of acceptance belongs to the person or class invited by the offer. The offeree must also know of the offer when acting. That point is especially important for rewards and other unilateral contracts: performance done without knowledge of the offer is not acceptance of that offer.

2. Bilateral and Unilateral Acceptance

Contract type What the offer requests When acceptance occurs

Bilateral A return promise. When the promise is made through the invited or reasonable method and notice rules are satisfied.

Unilateral Completed performance. Upon completion of the requested act; reasonable notice may be required when performance would not come to the offeror’s attention.

Beginning performance of a unilateral offer ordinarily does not complete acceptance, but the outlines use Restatement §45 to explain that it creates an option contract allowing a reasonable opportunity to finish.

3. Method and Notice

● Specified method: follow the offer’s exclusive instructions. ● No specified method: acceptance may be made by a reasonable manner and medium under the circumstances.

● Conduct: keeping goods, taking services, or acting inconsistently with the offeror’s ownership can manifest assent. ● Duty to read: a party may be bound by terms accepted even if the party chose not to read them, assuming reasonable notice and assent.

4. Silence Is Usually Not Acceptance - But Silence Plus Can Be

The default rule protects an offeree from being forced to reject unwanted bargains. Restatement §69 and the outlines recognize narrow situations where silence or inaction can manifest assent:

1 The offeree takes the benefit of services with a reasonable opportunity to reject and reason to know compensation is expected. 2 The offeror gave reason to understand silence may operate as assent, and the offeree intended to accept by remaining silent. 3 Prior dealings make it reasonable for the offeree to notify the offeror only if the offeree rejects. 4 The offeree exercises dominion over offered property in a manner inconsistent with the offeror’s ownership.

5. Common Law Requires a Mirror Image

At common law, acceptance must be positive and unequivocal. A response that changes, adds, subtracts, or qualifies a term is generally a counteroffer, not acceptance. A mere inquiry - “Would you consider delivery a week later?” - does not necessarily reject the original offer unless it communicates unwillingness to accept as stated.

6. Mailbox Rule

A properly addressed acceptance sent through an invited or reasonable medium is generally effective when dispatched - when it leaves the offeree’s possession - even if it is delayed or lost. Revocations and rejections are ordinarily effective upon receipt.

Key Takeaway

The rule does not control when the offer says acceptance is effective only upon receipt, when acceptance occurs through completed unilateral performance, or when an option contract requires the exercise to reach the offeror within the option period.

Key Takeaway

On Monday, Seller mails an offer. Buyer mails a proper acceptance Tuesday morning. Seller’s revocation reaches Buyer Tuesday afternoon. The acceptance ordinarily became effective when dispatched, before the revocation arrived. Change the offer to “acceptance effective only when received,” and the result can reverse.

Exam Tip

Identify the invited offeree; classify the offer as bilateral or unilateral; find the required or reasonable method; analyze notice; test silence-plus; apply the mirror-image rule; then calculate dispatch and receipt times.

Common Mistake

Do not say silence always equals rejection or acceptance. Do not apply the mailbox rule to option contracts without checking receipt. Do not treat a question about different terms as acceptance under common law.

Primary Authorities

  • ● Restatement (Second) of Contracts § 45 and § 69.

  • ● U.C.C. § 2-206.

  • ● Common-law mirror-image rule and mailbox rule.

Exam-ready conclusion

Acceptance is fact-specific assent. Match the response to the offer’s requested promise or performance, follow the required method, and keep dispatch rules separate from receipt rules.