Black-letter propositions
- 01
Common-law acceptance generally must mirror the offer; conditional or materially different assent may be a counteroffer.
- 02
Unless the offer provides otherwise, acceptance by an authorized noninstantaneous method is effective on dispatch.
- 03
Option-contract acceptance is generally effective on receipt.
- 04
A unilateral offer is accepted by completed performance, although beginning performance creates protection and notice may be required when the offeror would not reasonably learn of completion.
- 05
Silence is ordinarily not acceptance except through benefit-taking with reason to know payment is expected, prior dealings, or invited silence.
Use this attack sequence under time
Frame the issue
Identify invited mode and deadline.
Resolve the next checkpoint
Ask whether response is unequivocal or conditional.
Resolve the next checkpoint
Apply dispatch or receipt rule.
Finish the conclusion
For performance, determine beginning, completion, and notice.
Common wrong turns
- A misaddressed acceptance may lose mailbox protection.
- An acceptance following a rejection sent first creates a race: the first received ordinarily controls.
- Acceptance under an option is not protected on dispatch.
Worked example
An offeree mails a proper acceptance on Monday and receives a revocation on Tuesday.
If mail was authorized and no exception applies, the acceptance became effective on Monday's dispatch, forming a contract before the Tuesday revocation was received.
Practice this topic
How Article 2 treats acceptance
UCC 2-206(1)(a) says, unless otherwise unambiguously indicated, an offer to make a contract is construed as inviting acceptance in any manner and by any medium reasonable in the circumstances. Section 2-206(1)(b) says an order for prompt or current shipment invites acceptance either by a prompt promise to ship or by prompt shipment of conforming or non-conforming goods, but shipping non-conforming goods is not an acceptance if the seller seasonably notifies the buyer that it is offered only as an accommodation.
Section 2-206(2) covers a requested performance whose beginning is a reasonable mode of acceptance, and it requires the offeror to be notified of acceptance within a reasonable time or the offer may be treated as lapsed.
The mailbox rule and objective assent
Cornell describes the mailbox rule as the default rule that an offer is accepted the moment the offeree mails the letter, not when the offeror receives it. It can also apply to other means of communication if irrevocable once sent, parties can contract around it, and in most states it applies only to bilateral contracts. Cornell also says acceptance is judged objectively and may be express or implied from conduct, relayed in a manner authorized, requested or reasonably expected by the offeror.
A shipment of non-conforming goods under 2-206 is a special case, so separate it from the general acceptance analysis.
Frequently asked questions
What is the controlling rule for acceptance, mailbox rule, and unilateral performance?+
An authorized acceptance ordinarily forms a contract when dispatched, except where the offer, an option, or another rule requires receipt or completed performance.
How should I analyze acceptance, mailbox rule, and unilateral performance on the bar exam?+
Identify invited mode and deadline. Ask whether response is unequivocal or conditional. Apply dispatch or receipt rule. For performance, determine beginning, completion, and notice.
In what manner can an offer be accepted under UCC 2-206?+
Unless the language or circumstances unambiguously indicate otherwise, in any manner and by any medium reasonable in the circumstances, according to UCC 2-206(1)(a).
How can an order for prompt shipment be accepted?+
By a prompt promise to ship or by the prompt or current shipment of conforming or non-conforming goods, under UCC 2-206(1)(b).
Does shipping non-conforming goods always accept the offer?+
No. It is not an acceptance if the seller seasonably notifies the buyer that the shipment is offered only as an accommodation to the buyer.
What is the mailbox rule?+
The default rule that an offer is accepted the moment the offeree mails the acceptance, not when the offeror receives it, per Cornell's summary.
Can parties change the mailbox rule?+
Yes. Cornell says parties can contract around the mailbox rule to change when an offer is considered accepted, and that the rule varies from state to state.