The mail box rule is a judge made legal doctrine 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.
The mailbox rule states that an incarcerated pro se litigant's filing requirement is met when the pro se litigant delivers a document to prison authorities for mailing. [Faurot v. Barton, 2008 U.S. Dist. LEXIS 3818 (E.D. Cal. Jan. 4, 2008)]
The mailbox rule states that papers filed by a prisoner are deemed filed on the date they are given to prison authorities for mailing. [Salazar v. Hegerty, 2008 U.S. Dist. LEXIS 111071 (E.D. Wis. July 17, 2008)]
The mailbox rule is also known as dispatch rule.