Skip to Content

What makes a contract legally binding?

A legally binding contract is an agreement between two or more parties that is enforceable by law. For a contract to be valid and enforceable, it must contain certain elements. Understanding the basics of what makes a contract legally binding is important for anyone entering into an agreement, whether it’s a simple transaction or a complex business deal.

Key Elements of a Legally Binding Contract

There are four key elements that must be present for a contract to be legally enforceable:

  • Offer – One party makes an offer to enter into a contract. This could be a formal written document or a verbal agreement.
  • Acceptance – The other party unconditionally agrees to the terms of the offer.
  • Consideration – Something of value is exchanged between the parties. This could be money, property, services, etc.
  • Intent – Both parties intend to enter into a legally binding agreement and accept the terms of the contract.

If any of these elements are missing, the contract may not be valid and enforceable. Let’s look at each of these key components in more detail:


An offer is a clear proposal to enter into a contract. It expresses the willingness of the offering party to be bound to the contract upon acceptance. Here are some important things to know about the offer:

  • The offer must be definite and contain specific terms. Vague or unclear offers may not be enforceable.
  • Advertisements, catalogs, and invitations to negotiate are generally not considered valid offers.
  • Offers can be terminated or revoked at any time prior to acceptance.

Examples of an offer include a written proposal to buy property at a specific price, bid invitations for a construction project, or a sales quote for goods or services at fixed prices.


Acceptance refers to an unconditional agreement to the exact terms of the offer. Important requirements for proper acceptance include:

  • Acceptance must be communicated clearly and unambiguously.
  • Any counteroffers or changes to the terms of the offer generally constitutes a rejection.
  • Silence does not imply acceptance, unless otherwise specified.
  • The accepting party must have legal capacity to enter into a contract.

Ways in which acceptance can be conveyed include signing a contract, oral agreement, email confirmation, or performance/delivery of goods or services. For important contracts, written documentation is recommended to avoid any confusion about the terms.


Consideration refers to something of value given between parties to a contract. It is the bargained-for exchange that induces the parties to enter into the agreement. Requirements for consideration include:

  • It must have value in the eyes of the law.
  • It doesn’t need to be money – goods, services, promises, or waived rights can be valid consideration.
  • The consideration from each party does not need to be equal in value.
  • Past consideration is not valid (the exchange must be in the present contract).

A simple example is a contract for the sale of a bike for $100. The bike is consideration from the seller, while the money is consideration from the buyer. More complex contracts have multiple forms of consideration from each party.


Both parties to a contract must have a mutual intent to enter into a legally binding agreement. Certain agreements do not involve intent and are not legally enforceable contracts, such as:

  • Social arrangements or domestic agreements between family members.
  • Jokes or office betting pools.
  • Commitments to donate with no reciprocation.

When determining intent, courts will look at:

  • The words used in the agreement.
  • Whether the agreement was in writing.
  • If legal phrasing and terminology was utilized.
  • The setting of the agreement.

In business dealings, there is a presumption of intent to create legal relations. However, social and domestic agreements are assumed to lack intent unless shown otherwise.

Other Contract Requirements

In addition to the four basic elements, there are some other requirements that may apply to a contract. These include:


The parties entering into the contract must have full legal capacity. Those who lack capacity under the law include:

  • Minors (with some exceptions).
  • Mentally incapacitated persons.
  • Intoxicated individuals.
  • Corporations acting outside their powers.

Genuine Assent

The parties must voluntarily enter into the contract, without duress, undue influence or misrepresentation. Contracts signed under coercion or based on fraud can be rendered unenforceable.


The underlying purpose and subject matter of the contract must be legal. Agreements to commit crimes, violate public policy or restrain trade are unlawful contracts.


The contract terms must be possible to perform. A contract requiring an act prohibited by law or a physical impossibility is void.


Certain types of agreements require specific forms or execution formalities to be enforceable. Examples include real estate contracts, prenuptial agreements, and wills.

Breach of Contract

Despite the existence of a valid contract, one or both parties may fail to perform their contractual obligations. This constitutes a breach of contract, which can open the breaching party up to legal liability. Common types of breach include:

  • Partial breach – Failing to perform one or some of the contracted tasks or deliverables.
  • Minor breach – Non-performance of a contract term that is considered minor or inconsequential.
  • Material breach – Failure to perform a duty that substantially defeats the purpose of the contract.
  • Actual breach – One party fails to perform under the contract when performance is due.
  • Anticipatory breach – Before performance is due, one party communicates intent not to perform.

Remedies available to the non-breaching party depend on the severity and type of breach. They can include monetary damages, cancellation of the contract, obtaining a court order for performance, or other relief to make the non-breaching party whole.

Defenses to Enforcement

There are certain defenses that can make a contract unenforceable or allow a party to avoid their obligations under it. Common defenses include:

  • Unilateral mistake – One party is mistaken about a basic assumption regarding the contract.
  • Mutual mistake – Both parties are mistaken regarding facts vital to the contract.
  • Duress – A party is forced to consent to the contract through threats, coercion or undue influence.
  • Undue influence – A party uses manipulation or a position of power to obtain unfair consent.
  • Misrepresentation – Intentionally false statements are made to induce a party to contract.
  • Unconscionability – Terms are unreasonably favorable to one party, undermining consent.
  • Incapacity – A party lacks legal capacity to validly consent.

A successful defense makes the contract void or voidable at the election of the party seeking to avoid enforcement. However, defenses are not easily proven in court.

Statute of Frauds

The statute of frauds requires certain types of contracts to be in writing to be enforceable. Agreements that generally must comply with the statute of frauds include:

  • Contracts for the sale of land.
  • Leases exceeding one year in duration.
  • Agreements for goods over $500.
  • Contracts that cannot be performed within one year.
  • Promises to pay the debt of another (“guarantees”).
  • Contracts made in consideration of marriage.

These contracts must at least be evidenced by some signed note or memorandum containing the key terms and parties, even if they are not formally executed. Contracts outside the scope of the statute of frauds can be oral and still enforceable.

Parol Evidence Rule

The parol evidence rule limits the ability to supplement or change a written contract with external evidence:

  • Oral discussions before or at signing cannot be used to change the terms of a written agreement.
  • Prior negotiations and communications are merged into the final contract.
  • Oral testimony can only be used to clarify ambiguities, not add or contradict terms.

The purpose is to avoid fights over “he-said-she-said” verbal agreements when there is a clear written contract. However, there are exceptions when evidence of fraudulent inducement or subsequent modifications may be allowed.


Entering into legally binding contracts is a key part of business and commerce. When all the required elements are present, parties can rely on their agreements being enforceable in court. Understanding the basics of contract validity ensures you structure agreements carefully to avoid disputes. If issues do arise, defenses may provide a way out under the right facts. Seeking legal counsel is advisable before signing any complex or high-value contracts to protect your rights and obligations.