Acceptance and the legal rules for a valid acceptance

Definition. Under section 2(b) of the Indian Contract Act, 1872, “when the person to whom the proposal is made signifies his assent thereto, the proposal is said to be accepted; a proposal, when accepted, becomes a promise”. Anson compared acceptance to a lighted match applied to a train of gunpowder: an offer by itself creates no legal relationship, but once accepted it becomes a promise and can no longer be revoked.

Legal rules regarding a valid acceptance:

1. Only by the person to whom the offer is made. A specific offer can be accepted only by the offeree (Boulton v. Jones: goods supplied by the buyer of a business on an order addressed to its former owner created no contract). A general offer can be accepted by anyone who knows of it (Carlill v. Carbolic Smoke Ball Co.).
2. Absolute and unqualified (s. 7). A conditional or qualified acceptance is a counter offer and rejects the original offer.
3. Communicated to the offeror. Acceptance must be communicated; a mere resolve in the offeree's mind is not enough.
4. In the prescribed mode. If the offer prescribes a mode, acceptance must follow it; if it is accepted otherwise and the offeror does not insist on the prescribed mode, he is taken to have consented.
5. Within the time fixed or a reasonable time, before the offer lapses or is revoked.
6. Mere silence is not acceptance, unless the offeree's previous conduct shows that silence means assent.
7. May be express or implied by conduct.
8. After the offer. Acceptance in ignorance of the offer, or before it is made, is no acceptance.

Communication of “acceptance is complete as against the proposer when it is put in” “course of transmission to him, so as to be out of the” acceptor's power, and as against the acceptor when it comes to the proposer's knowledge (s. 4).