Commerce · Ch 29 — Elements of Contract

Classification of Contracts

Contracts can be classified on three different bases.

(A) On the basis of validity/enforceability

Type	Meaning	Example
Valid contract	Has all essential elements; fully enforceable	A agrees to sell his car to B for a fixed price, both competent, consent free
Void agreement	Not enforceable by law at all, from the start or later	An agreement with a minor; an agreement to do an impossible act
Voidable contract	Enforceable at the option of one party only, the other's consent not being free	A contract induced by coercion or fraud — the aggrieved party may affirm or repudiate it
Illegal agreement	Forbidden by law; also affects collateral transactions	An agreement to smuggle goods
Unenforceable contract	Valid in substance, but cannot be enforced due to a technical defect (e.g. missing a required stamp/writing)	An agreement requiring registration that was never registered

(B) On the basis of formation

Express contract — terms are stated in words, spoken or written.
Implied contract — terms are inferred from the conduct of parties or the circumstances (e.g. boarding a bus implies a promise to pay the fare).
Quasi-contract — not a contract at all in the true sense, but an obligation the law imposes on a person to prevent unjust enrichment, as if a contract existed (e.g. a finder of lost goods is bound to return them, or a person who is supplied necessaries must pay a reasonable price).
E-contract — a contract formed through electronic means, such as online orders and click-wrap agreements, now increasingly common in commerce.

(C) On the basis of performance

Executed contract — both parties have completely performed their obligations.
Executory contract — performance by one or both parties is yet to be completed. …