7.2 Classification of contracts

Based on formation
Express contract: An express contract is one in which the terms and conditions are explicitly stated, either in writing or verbally, at the time of agreement.
Implied contract: An implied contract is formed based on the conduct of the parties or the circumstances of the situation, even though there may not be a formal, explicit agreement. Implied contracts are often referred to as “quasi-contracts.”
Unilateral contract: In a unilateral contract, one party makes a promise in exchange for the other party’s performance. The contract is formed when the performance is completed.
Bilateral contract: A bilateral contract is one in which both parties exchange promises to perform certain acts. For example, in a sales contract, the buyer promises to pay, and the seller promises to deliver the goods. Most contracts are bilateral.

Based on enforceability
Valid contract: A valid contract meets all the legal requirements and elements necessary to be enforceable. It has a valid offer, acceptance, consideration, legal capacity, a lawful purpose, and clear terms.
Void contract: A void contract is not valid from the beginning because it lacks one or more essential elements, such as a lawful purpose. It is treated as if it never existed and is not enforceable by either party.
Voidable contract: A voidable contract is valid unless one party chooses to void (cancel) it due to factors such as fraud, duress, undue influence, or a lack of capacity. The party with the option to void can either affirm or cancel the contract.
Unenforceable contract: An unenforceable contract is one that may have been valid initially but cannot be enforced in court due to a legal technicality. For example, a contract that violates the Statute of Frauds may be unenforceable.

Based on performance
Executed contract: An executed contract is one in which all parties have fully performed their obligations. The contract is completed, and nothing remains outstanding.. Executory contract: An executory contract is one in which one or more parties have not yet fulfilled their obligations. Some or all of the agreed-upon actions or deliveries are pending.
1. Based on nature
2. Unilateral contract: As mentioned earlier, a unilateral contract involves one party making a promise in exchange for the other party’s performance.
3. Specialty (or specialty contract): A specialty contract is a formal written contract that is typically executed under seal. It often involves significant transactions, such as real estate transactions.
4. Simple (or simple contract): A simple contract is an informal contract that does not require a seal or a formal written document.
1. Based on Validity of Assent
2. Valid contract: A valid contract is formed when the parties involved have freely and genuinely consented to the agreement without any defects in their understanding or willingness.
3. Voidable contract: A voidable contract may appear valid but can be voided by one party due to factors like fraud, misrepresentation, duress, or undue influence, which impair the party’s consent.
1. Based on time frame
2. Executed contract: As mentioned earlier, an executed contract is one in which all parties have performed their obligations.
3. Executory contract: An executory contract is one in which performance is to occur in the future, and obligations are not yet fulfilled.