A contract is an agreement between two or more parties that creates obligations enforceable by law. It defines what each party has promised to do, provide, pay, permit, or avoid doing—and may give the affected party a legal remedy when those promises are not performed.
Contracts appear throughout everyday and commercial life. Employment offers, leases, purchase orders, service agreements, software subscriptions, and online terms can all create contractual relationships.
A contract does not always need to be a long paper document filled with legal language. Depending on the transaction and governing law, it may be written, electronic, verbal, or inferred from the parties' conduct.
This article provides general educational information and is not legal advice. Contract requirements and enforceability vary by jurisdiction and circumstances.
What Is the Legal Definition of a Contract?
Cornell Law School's Legal Information Institute defines a contract as an agreement between parties that creates mutual obligations enforceable by law.
The defining feature is enforceability. People make promises and informal arrangements every day, but not every promise gives the other person a legal right to demand performance or compensation.
A contract generally establishes:
• Who the parties are
• What each party must do or provide
• What value is being exchanged
• When and how performance must occur
• How changes will be approved
• What happens if a party fails to perform
• How the relationship may end
The document's title is not decisive. A document called an agreement, order form, statement of work, purchase order, or terms of service may operate as a contract if it contains the necessary elements and demonstrates an intention to create binding obligations.
What Is the Difference Between a Contract and an Agreement?
An agreement is a mutual understanding between two or more parties. A contract is an agreement that satisfies the applicable requirements for legal enforceability.
In simple terms, every contract is an agreement, but not every agreement is a contract.
For example, two colleagues might agree to have lunch next week. They have reached an agreement, but they probably do not intend to create legal obligations.
By contrast, a company may agree to pay a consultant $10,000 to complete a defined project by a specified date. If the necessary legal elements are present, that arrangement may be an enforceable contract.
Cornell LII's explanation of an agreement notes that an agreement generally reflects mutual assent, while a contract normally requires additional elements such as consideration.
Substance matters more than the document's name. Calling a document a proposal, memorandum, letter, or agreement does not necessarily prevent it from becoming legally binding.
What Are the Essential Elements of a Contract?
The exact requirements vary by jurisdiction and transaction. A practical analysis commonly considers six elements.
1. Offer
An offer is a sufficiently definite proposal to enter into an agreement. It communicates what one party is prepared to do if the other party accepts.
For example, “We will deliver 500 units by June 30 for $20,000” identifies the product, quantity, deadline, and price. A statement such as “We may be able to supply some products later” is less likely to constitute a definite offer.
2. Acceptance
Acceptance occurs when the recipient agrees to the offer in the required manner.
Acceptance may be communicated through a signature, written confirmation, verbal statement, payment, performance, or other conduct demonstrating agreement.
If the recipient changes a material term, the response may be a counteroffer rather than acceptance.
3. Mutual Assent
Mutual assent means the parties objectively demonstrate agreement to the essential terms. It is sometimes described as a “meeting of the minds.”
There should be sufficient certainty about the identity of the parties, the subject of the transaction, and the material obligations. Unresolved pricing, contradictory documents, or vague responsibilities can create uncertainty about what was agreed.
4. Consideration
Consideration is the value exchanged between the parties. Each side generally gives, promises, or gives up something in return for the other party's promise.
Consideration may include:
• Money
• Goods or services
• Access or licensing rights
• A promise to perform an action
• A promise not to exercise an existing right
Cornell LII's explanation of consideration notes that the parties generally must assume some obligation rather than rely on a purely gratuitous promise.
5. Capacity and Authority
The parties must have the legal capacity to enter into the agreement. Capacity may be affected by age, mental condition, guardianship, intoxication, or other circumstances recognized by law.
When a person signs for a company, that person should also have authority to bind the organization.
6. Lawful Purpose
A contract's purpose and material terms must be lawful. An agreement involving illegal conduct does not become enforceable simply because the parties wrote it down and signed it.
Legality may also depend on licensing requirements, employment rules, consumer protections, industry regulations, and public policy.
How Is a Contract Formed?
Contract formation is the process through which the parties move from a proposed transaction to an enforceable agreement.
1. One party makes an offer. The offer describes the proposed transaction and its essential terms.
2. The other party evaluates the offer. It may accept, reject, request clarification, or propose different terms.
3. The parties negotiate. They may exchange drafts, comments, redlines, order forms, emails, and supporting documents.
4. The material terms are agreed. The parties reach sufficient agreement on the obligations, consideration, timing, and other essential provisions.
5. The authorized parties accept the agreement. Acceptance may occur through signature, electronic confirmation, performance, or another legally recognized method.
6. The contract becomes effective. The effective date may be the signature date, a specified date, or the date on which a stated condition is satisfied.
Commercial contracts may include several connected documents. The final agreement should identify which documents apply and which one controls if their terms conflict.
Does a Contract Have to Be Written or Signed?
Not every contract must be written. Depending on the governing law and circumstances, verbal and implied contracts may be enforceable.
However, some agreements must be documented in writing. The statute of frauds commonly applies to categories such as transfers of land and agreements that cannot be completed within one year.
For certain sales of goods governed by the Uniform Commercial Code, UCC § 2-201 generally requires a sufficient signed writing for contracts involving goods priced at $500 or more, subject to stated exceptions.
Even when a verbal contract may be valid, written documentation usually provides greater clarity and stronger evidence of:
• The agreed scope
• Pricing and payment obligations
• Deadlines and milestones
• Ownership and confidentiality terms
• Renewal and termination rights
• The version accepted by the parties
Electronic contracts and signatures may also have legal effect. Under the federal E-SIGN Act, a covered signature, contract, or record generally may not be denied legal effect solely because it is electronic.
The underlying agreement must still satisfy the applicable requirements for contract formation.
What Are the Main Types of Contracts?
Contracts may be classified by how they are formed and what the parties have promised.
Written Contract
A written contract records the agreement in a physical or electronic document. It is generally the clearest format for complex, valuable, or higher-risk transactions.
Verbal Contract
A verbal contract is created through spoken communication. It may be enforceable if the required elements are present and the law does not require a written record.
The main practical difficulty is proving exactly what was agreed.
Express Contract
An express contract states its terms through written or spoken words. The parties communicate their commitments directly.
Implied Contract
An implied contract may arise from the parties' conduct rather than an explicit written or verbal agreement.
For example, a customer who orders and receives a standard service may be expected to pay the usual price even if every term was not negotiated in advance.
Bilateral Contract
A bilateral contract involves an exchange of promises. A supplier promises to deliver goods, while the customer promises to pay the agreed price.
Most commercial contracts are bilateral.
Unilateral Contract
A unilateral contract involves a promise made in exchange for a specified action. A reward offered for returning lost property is a common example.
Executed and Executory Contracts
An executed contract has been fully performed.
An executory contract still contains obligations that must be completed. A signed two-year service agreement remains executory while services and payments continue.
What Are Common Business Contracts?
Businesses use different agreements for different relationships and transactions.
Common examples include:
• Sales and purchase agreements
• Service agreements
• Employment and contractor agreements
• Commercial leases
• Licensing agreements
• Distribution and reseller agreements
• Software and SaaS agreements
• Data-processing agreements
• Purchase orders and order forms
• Statements of work
A non-disclosure agreement protects specified confidential information and limits how the receiving party may use or disclose it.
A master service agreement establishes the general legal and commercial terms for an ongoing service relationship. Individual projects may then be documented through statements of work or order forms.
What Should a Business Contract Include?
The appropriate provisions depend on the transaction, industry, parties, and allocation of risk. A commercial contract commonly addresses:
• The parties' correct legal names
• Scope, deliverables, responsibilities, and exclusions
• Pricing, invoicing, expenses, taxes, and payment deadlines
• Contract term, renewal, and notice periods
• Intellectual-property ownership and licenses
• Confidentiality, privacy, and security requirements
• Warranties and performance standards
• Indemnification obligations
• Liability caps and excluded damages
• Change-control procedures
• Termination rights and cure periods
• Governing law and dispute resolution
• Document precedence and amendment procedures
A useful contract should do more than sound legally formal. It should allow the parties to determine who is responsible, what must be delivered, when performance is due, how success will be measured, and what happens when circumstances change.
For guidance on producing the document, see What Is Contract Authoring and Drafting? and How to Draft a Contract.
What Happens When a Contract Is Breached?
A breach of contract occurs when a party fails to perform an obligation required by the agreement.
Examples include:
• Failing to make a payment
• Delivering goods late or in the wrong quantity
• Providing services that do not meet the agreed standard
• Disclosing protected confidential information
• Refusing to complete a required obligation
• Ending the agreement without a contractual right
The contract may require the affected party to give written notice and allow time for the problem to be corrected before suspending performance or terminating the agreement.
Possible remedies include monetary damages, restitution, agreed liquidated damages, injunctive relief, termination, and specific performance in limited circumstances.
Cornell LII's overview of breach of contract explains that monetary damages commonly aim to place the harmed party in the economic position it would have occupied if the contract had been performed.
The available remedy depends on the contract, applicable law, seriousness of the breach, and loss suffered.
How Should You Review a Contract Before Signing?
Contract review should confirm both legal protection and operational feasibility.
Before signing, check:
• Whether the parties are correctly identified
• Whether the signer has authority
• Whether the scope and deliverables are clear
• Whether pricing and payment terms match the commercial deal
• Whether deadlines and dependencies are realistic
• Who owns intellectual property and data
• Whether confidentiality and security obligations are workable
• How warranties, indemnities, and liabilities interact
• How the contract renews or terminates
• Which document controls if terms conflict
• Whether definitions, dates, schedules, and cross-references are consistent
A favorable clause may be weakened by a definition, exception, schedule, or precedence provision elsewhere in the contract. The agreement should therefore be reviewed as a connected system.
See How to Review a Contract for a structured review process.
How Can Alloomi Help with Contracts?
Alloomi AI supports contract drafting and review by connecting the agreement with relevant matter facts, client instructions, document versions, approved templates, previous decisions, and professional review standards.
For contract work, Alloomi can help teams:
• Prepare working drafts from approved templates and deal information
• Identify missing information and open questions
• Compare versions and surface material changes
• Analyze rights, obligations, deadlines, and risk allocation
• Detect conflicting provisions and document-precedence issues
• Prepare suggested revisions for professional review
• Keep sources, reasoning, and revision history available
Alloomi helps professionals spend less time reconstructing context and more time applying judgment to the provisions that matter.
Frequently Asked Questions
Is Every Agreement a Contract?
No. An agreement becomes a contract when it satisfies the applicable requirements for legal enforceability. Informal understandings, incomplete negotiations, and promises lacking consideration may not create enforceable contracts.
Does a Contract Need a Signature?
Not always. Depending on applicable law, acceptance may be shown through words, electronic confirmation, payment, performance, or other conduct.
However, some agreements must be written and signed. A signature also provides stronger evidence that the party accepted the identified version.
Can a Verbal Agreement Be a Contract?
Yes. A verbal agreement may form a contract when the required elements are present and the law does not require a written record. Proving the exact terms of a verbal contract can be difficult, so important agreements should generally be documented.
Can an Email Create a Contract?
Potentially. An email exchange may create or provide evidence of a contract if it demonstrates a definite offer, acceptance, consideration, authority, and an intention to be bound.
Whether a particular email exchange creates a contract depends on its language, context, completeness, and governing law.
Can a Contract Be Changed After Signing?
Yes. The parties may amend a contract by following its modification procedure and applicable law. Many contracts require amendments to be recorded in writing and signed by authorized representatives.
The amendment should be stored with the original agreement so the complete set of current terms remains available.
Can AI Draft or Review a Contract?
AI can prepare working language, compare versions, identify clauses, summarize obligations, and surface potential issues. Alloomi AI can support these workflows by connecting the contract with matter facts, approved standards, previous decisions, and related documents. Important conclusions and final language should still be reviewed by a qualified professional.
