The mail box rule is a judge made legal doctine of contract law that finds the acceptance of an offer is made as of the time the acceptance is placed in a mail box, as long as mailing an accepting reply is a reasonable form of acceptance. The acceptance is effective at the time of sending. However, the mail box rule does not apply to revocations of an acceptance, which are only effective when received.
In order for the mailbox rule to apply, the acceptance must be dispatched within the time in which the offer must be accepted, and will not apply if the offer requires acceptance by personal delivery on or before the specified date. The mailbox rule is sometimes also applied in situations involving payment of insurance premiums.
