Contract Law
Part of the common law series
Contract theory
Contract formation
Offer and acceptance  · Mailbox rule
Mirror image rule  · Invitation to treat
Consideration
Defenses against formation
Lack of capacity to contract
Duress  · Undue influence
Illusory promise  · Statute of frauds
Non est factum
Contract interpretation
Parol evidence rule
Contract of adhesion
Integration clause
Contra proferentem
Excuses for non-performance
Mistake  · Misrepresentation
Frustration of purpose  · Impossibility
Unclean hands  · Unconscionability
Illegality  · Accord and satisfaction
Rights of third parties
Privity of contract
Assignment  · Delegation
Novation  · Third party beneficiary
Breach of contract
Anticipatory repudiation  · Cover
Exclusion clause
Fundamental breach
Remedies
Specific performance
Liquidated damages
Penal damages  · Rescission
Quasi-contractual obligations
Promissory estoppel
Quantum meruit
Subsets: Conflict of law Commercial law
Other areas of the common law
Tort law  · Property law
Wills and trusts
Criminal law  · Evidence

The mailbox rule or the postal acceptance rule is a term of common law contracts which determines the timing of acceptance of an offer when mail is contemplated as the medium of acceptance. The general principle is that a contract is formed when acceptance is actually communicated to the offeror. The mailbox rule is an exception to the general principle. The mailbox rule provides that the contract is formed when the letter of acceptance is placed in the mailbox. Image File history File links Scale_of_justice. ... A contract is a promise or an agreement made of a set of promises. ... This article concerns the common-law legal system, as contrasted with the civil law legal system; for other meanings of the term, within the field of law, see common law (disambiguation). ... Contract theory comprises many different theories and various interpretations of the various body of rules and subrules that define Contract Law. ... Offer and acceptance analysis is a traditional approach in contract law used to determine whether an agreement exists between two parties. ... In the law of contracts, the mirror image rule states that an offer must be accepted exactly without modifications. ... In contract law, an invitation to treat (invitation to bargain in the US) is an action by one party which may appear to be a contractual offer but which is actually inviting others to make an offer of their own. ... It has been suggested that this article or section be merged with Consideration under English law. ... The capacity of both natural and artificial persons determines whether they may make binding amendments to their rights, duties and obligations, such as getting married or merging, entering into contracts, making gifts, or writing a valid will. ... Duress in the context of contract law is a common law defence, and if you are successful in proving that the contract is vitiated by duress, you can rescind the contract, since it is then voidable. ... Undue influence (as a term in jurisprudence) is an equitable doctrine that involves one person taking advantage of a position of power over another person. ... In contract law, an illusory promise is one that courts will not enforce. ... The statute of frauds refers to a requirement in many common law jurisdictions that certain kinds of contracts, typically contractual obligations, be done in writing. ... This article or section does not cite its references or sources. ... This article or section does not cite its references or sources. ... A standard form contract (sometimes referred to as an adhesion contract or boilerplate contract) is a contract between two parties that does not allow for negotiation, i. ... An integration clause, in the contract law, is a term in the language of the contract that declares it to be the complete and final agreement between the parties. ... Contra preferendum or contra preferentem is the rule in contract law that is applied when interpreting a clause, especially an exclusion clause, in an action that says that, where ambiguity as to a terms meaning exists, it should be read against the party who wrote it. ... In contract law a mistake is incorrect understanding by one or more parties to a contract and may be used as grounds to invalidate the agreement. ... In contract law, a misrepresentation is a false statement of fact made by one party to another party and has the effect of inducing that party into the contract. ... Frustration of purpose is a term used in the law of contracts to describe a defense to an action for non-performance based on the occurance of an unforseen event which makes performance impossible or commercially impracticable. ... Impossible is also a name of a skateboarding trick. ... This article or section does not cite its references or sources. ... This article or section does not cite its references or sources. ... An illegal agreement, under the common law of contract, is one that the courts will not enforce because the purpose of the agreement is to achieve an illegal end. ... Accord and satisfaction is the purchase of the release from a debt obligation. ... The doctrine of privity in English law provides that a contract cannot confer rights or impose obligations arising under it on any person or agent except the parties to it. ... An assignment is a term used with similar meanings in the law of contracts and in the law of real estate. ... Delegation is a term used in the law of contracts to describe the act of giving another person the responsibility of carrying out the performance agreed to in a contract. ... Novation is a term used in contract law and business law to describe the act of either replacing an obligation to perform with a new obligation, or replacing a party to an agreement with a new party. ... A third party beneficiary, in the law of contracts, is a person who may have the right to sue on a contract, despite not having originally been a party to the contract. ... Breach of contract is a legal concept in which a binding agreement or bargained-for exchange is not honored by one of the parties to the contract by non-performance or interference with the other partys performance. ... Anticipatory repudiation (or anticipatory breach) is a term in the law of contracts that describes a declaration by one party (the promissing party) to a contract that they do not intend to live up to their obligations under the contract. ... Cover is a term used in the law of contracts to describe a remedy available to a merchant buyer who has received an anticipatory repudiation of a contract for the receipt of goods. ... An exclusion clause is a term in a contract that seeks to restrict the rights of the parties to the contract. ... Fundamental breach, sometimes known as a repudiatory breach, is a breach so fundamental that it permits the aggrieved party to terminate performance of the contract, in addition to entitling that party to sue for damages. ... Definition of Specific performance In the law of remedies, a specific performance is a demand of a party to perform a specific act. ... Liquidated damages is a term used in the law of contracts to describe a contractual term which establishes damages to be paid to one party if the other party should breach the contract. ... Penal damages are best seen as quantitatively excessive liquidated damages and are invalid under the common law. ... In contract law, rescission (to rescind or set aside a contract) refers to the cancellation of the contract between the parties. ... Estoppel is a concept that prevents a party from acting in a certain way because it is not equitable to do so. ... Quantum meruit is a Latin phrase meaning as much as he has deserved. In the context of contract law, it means something along the lines of reasonable value of services. Situations The concept of quantum meruit applies to the following situations: I. When a person employs (impliedly or expressly) another... International private law, private international law or conflict of laws is the branch of private law which regulates lawsuits involving foreign laws or jurisdictions. ... Commercial law or business law is the body of law which governs business and commerce and is often considered to be a branch of civil law and deals both with issues of private law and public law. ... In the common law, a tort is a civil wrong for which the law provides a remedy. ... Property law is the area of law that governs the various forms of ownership in real property (land as distinct from personal or movable possessions) and in personal property, within the common law legal system. ... In the common law, a will or testament is a document by which a person (the testator) regulates the rights of others over his property or family after death. ... The law of trusts and estates is generally considered the body of law which governs the management of personal affairs and the disposition of property of an individual in anticipation and the event of such persons incapacity or death, also known as the law of successions in civil law. ... Criminal law (also known as penal law) is the body of statutory and common law that deals with crime and the legal punishment of criminal offenses. ... The law of evidence governs the use of testimony (e. ... This article concerns the common-law legal system, as contrasted with the civil law legal system; for other meanings of the term, within the field of law, see common law (disambiguation). ... A contract is any promise or set of promises made by one party to another for the breach of which the law provides a remedy. ... Acceptance, in spirituality, mindfulness, and human psychology, usually refers to the experience of a situation without an intention to change that situation. ... Offer and acceptance analysis is a tool in contract law used to determine whether a contract exists between two parties. ... A British pillar box. ...

The leading case in the mailbox rule is Henthorn v Fraser [1892] 2 Ch 77 which was based in part on the earlier case of Adams v Lindsell (1818) B & Ald 681.

The mailbox rule only applies to acceptance; other letters do not take effect until the letter is delivered as in Stevenson v McLean (1880) 5 QBD 346. The implication of this is that it is possible for a letter of acceptance to be posted after a letter of revocation of the offer has been posted, but before it is delivered, and acceptance will be complete at the time that the letter of acceptance was posted.

For example, suppose A makes an offer to B on January 1; A then decides to revoke the offer on January 2, and puts a letter in the mail to B revoking the offer; however, B puts a letter accepting the offer in the mail on January 3, and does not receive A's revocation letter until January 4. The letter of revocation can only be effective when received, that is January 4. However, the contract was formed on January 3 when the letter of acceptance was posted. It is too late to revoke the offer.

Suppose that A makes an offer to B on January 1, and initially B intends to reject the offer on January 2 by putting a letter in the mail to A rejecting the offer. However, the next day B changes his mind and sends a fax to A accepting the offer. In this situation, whichever communication A receives first will govern. A Samsung fax machine. ...

Under the mailbox rule, performance is a means of acceptance. If A orders 1000 blue coathangers, and B ships them out, that shipment is considered to be a conveyance of acceptance of A's offer to buy the coathangers. Defective performance is also an acceptance, unless accompanied by an explanation. For example, if A orders 1000 blue coathangers, and B mistakenly ships 1000 red coathangers, this is still an acceptance of the contract. However, if B ships the red coathangers with a note that they sent these because they had run out of blue coathangers, this is not an acceptance, but rather an accommodation, which is a form of counter-offer. Accommodation is a term used in United States contract law under the Uniform Commercial Code to describes a delivery of nonconforming goods meant as a partial performance of a contract for the sale of goods, where a full performance is not possible. ... Offer and acceptance analysis is a traditional approach in contract law used to determine whether an agreement exists between two parties. ...

An interesting implication of the operation of the mailbox rule is that as acceptance is complete once the letter of acceptance is posted, it makes no difference whether the offeror actually receives the letter. This was demonstrated in Byrne v Van Tienhoven (1880) 5 CPD 344. If a letter of acceptance were to be lost, acceptance has still taken place. An exception to this would be if the offeree knows or has reason to know that the letter of acceptance never reached the offeror. For example, if A brings a letter of acceptance to the local post office, and A sees the post office burn down, there is no acceptance. Offer and acceptance analysis is a traditional approach in contract law used to determine whether an agreement exists between two parties. ... Offer and acceptance analysis is a traditional approach in contract law used to determine whether an agreement exists between two parties. ...

The mailbox rule does not apply to instantaneous forms of communications. For example in Entores Ltd v Miles Far East Corporation [1955] 2 QB 327, the Court held that the mailbox rule did not apply to an acceptance by telex as the Court regarded it as an instantaneously form of communication. The general principle that acceptance takes place when communicated applies to instantaneous forms of communication. Courts have similarly held that the mailbox rule does not apply to acceptances by telephone or fax. Entores Ltd. ... Telex can refer to more than one thing: For the communications network, see Telegraphy. ... Look up Telephone in Wiktionary, the free dictionary. ... A Samsung fax machine. ...

The courts are yet to decide whether e-mail should be regarded as an instantaneous form of communication. If the offeree were to convey acceptance by commercially unreasonable means - by cross-country pony express, for example - the acceptance would not be effective until it had actually been received. Wikipedia does not yet have an article with this exact name. ... Pony Express statue in St. ...

A letter is regarded as "posted" only when it is in the possession of the Post Office; this was established in the case of Re London & Northern Bank [1900] 1 Ch 220. A letter of acceptance is not considered "posted" if it is handed to an agent to deliver, such as a courier. Small-town post office and town hall in Lockhart, Alabama A post office is a facility (in most countries, a government one) where the public can purchase postage stamps for mailing correspondence or merchandise, and also drop off or pick up packages or other special-delivery items. ...

The mailbox rule does not apply to option contracts or irrevocable offers, where acceptance is still only effective upon receipt. This is because the offeree no longer needs protection against subsequently mailed revocations of the offer.

See also

• Offer and acceptance