In the law of

contract A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tr ...

s, the mirror image rule, also referred to as an unequivocal and absolute acceptance requirement, states that an

offer Offer or offers may refer to: People * Ofer Eshed or Offer Eshed (1942-2007), Israeli basketball player * Offer Nissim (born 1964), Israeli house DJ * Avner Offer, economic historian * Dick Offer, English rower * Jack Offer, English rower * Steve ...

must be accepted exactly with no modifications. The offeror is the master of their own offer. An attempt to accept the offer on different terms instead creates a counter-offer, and this constitutes a rejection of the original offer.

England

The

English common law English law is the common law legal system of England and Wales, comprising mainly criminal law and civil law, each branch having its own courts and procedures. Principal elements of English law Although the common law has, historically, be ...

established the concepts of ''

consensus ad idem Meeting of the minds (also referred to as mutual agreement, mutual assent or ''consensus ad idem'') is a phrase in contract law used to describe the intentions of the parties forming the contract. In particular, it refers to the situation where t ...

'', offer, acceptance and counter-offer. The leading case on counter-offer is ''

Hyde v Wrench ''Hyde v Wrench'' offers._In_it_Henry_Bickersteth,_1st_Baron_Langdale.html" ;"title="Offer_and_acceptance.html" ;"title="English_contract_law.html" ;"title="840EWHC Ch J90is a leading English contract law">840EWHC Ch J90is a leading English con ...

840 __NOTOC__ Year 840 ( DCCCXL) was a leap year starting on Thursday in the Julian calendar, the 840th year of the Common Era (CE) and Anno Domini (AD) designations, the 840th year of the 1st millennium, the 40th year of the 9th century, and the ...

The phrase "Mirror-Image Rule" is rarely (if at all) used by English lawyers; but the concept remains valid, as in ''

Gibson v Manchester City Council is an English contract law case in which the House of Lords strongly reasserted that agreement only exists when there is a clear offer mirrored by a clear acceptance. Facts Manchester City Council was being run by the Conservative Party, which ...

979 Year 979 ( CMLXXIX) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire * March 24 – Second Battle of Pankaleia: An Ibero-Byzantine expeditionary ...

and '' Butler Machine Tool v Excello''.

Australia

This position is adhered to in

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

(

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

). If a person were to accept an offer, but make a modification, then they are actually rejecting the offer presented to them and are proposing a counter-offer: ''Masters v Cameron'' (1954) 91 CLR 353. That modifying party is then the one making a new offer, and the original offeror is now the one who has to accept.

United States

In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, this rule still exists at common law. However, the

Uniform Commercial Code The Uniform Commercial Code (UCC), first published in 1952, is one of a number of Uniform Acts that have been established as law with the goal of harmonizing the laws of sales and other commercial transactions across the United States through U ...

("UCC") dispenses with it in § 2-207 (but it can also be argued that § 2-207(1) enforces the mirror image rule).Text of § 2-207: https://www.law.cornell.edu/ucc/2/article2.htm#s2-207 Therefore, its applicability depends upon what law governs. Most states have adopted the UCC, which governs transactions in goods. Contracts for services or land, for example, would not be governed by the UCC. The 2nd restatement of contracts also provides that when parties have not agreed to an essential term, "a term which is reasonable in the circumstances is supplied by the court." However, it may not be possible for a reasonable term to be supplied by the court.

References

{{reflist Contract law Legal doctrines and principles