To make a legal contract between two parties, you need five things in place — an offer, acceptance, consideration, legal capacity, and a lawful purpose — captured in a clear written document that both people sign. Get those right, and a court will enforce what you agreed to. Miss one, and what you have is a promise, not a contract.
The Five Elements a Contract Needs
An offer is a specific proposal: “I’ll redesign your website for $3,000, delivered by March 15.” It has to be definite enough that both sides know what’s on the table. “I could probably help you out sometime” doesn’t cut it.
Acceptance means the other party agrees to those exact terms. Change the price or the deadline in response and you haven’t accepted; you’ve made a counteroffer, and the original offer is dead. Acceptance can be spoken, written, or shown through conduct, but it has to mirror the offer.
Consideration is what each side gives up. Usually it’s money on one side and goods, services, or a promise on the other. The exchange doesn’t have to be equal in value; courts rarely second-guess whether someone got a good deal. What matters is that both parties are giving something.
Legal capacity means both signers are old enough and mentally able to understand what they’re agreeing to. In nearly every state, that’s 18 or older. A contract signed by a minor is voidable at the minor’s option: the minor can walk away, but the adult cannot. Someone who lacks the mental ability to understand the agreement can also void it.
Lawful purpose is the last piece. An agreement to do something illegal is void from the start, no matter how carefully it’s drafted. A contract to sell stolen goods gives neither side any enforceable rights.
When It Has to Be in Writing
Oral contracts are generally enforceable. Two people can shake hands and be bound. The problem is proving what was actually agreed when memories drift six months later. For anything beyond the simplest transaction, writing it down is dramatically easier to enforce.
A doctrine called the Statute of Frauds also requires certain categories of contracts to be written. Rules vary by state, but these types almost always need to be in writing:
- Sales, mortgages, or leases of real estate (short-term leases of a year or less are often exempt).
- Agreements that cannot possibly be completed within 12 months of the date they’re made. A seven-month project starting six months from now is a 13-month commitment and falls under the rule.
- Sales of goods at or above $500 under the Uniform Commercial Code, though the revised UCC raises the threshold to $5,000 in states that have adopted the update.
- Promises to pay someone else’s debt as a guarantor.
- Agreements made in consideration of marriage, including prenuptial agreements.
The writing doesn’t need to be a formal contract. A signed letter, email, or text message chain can satisfy the requirement in some jurisdictions, as long as it identifies the parties, describes the essential terms, and is signed by the person being held to it. A proper contract is still far safer than reconstructing a deal out of scattered messages.
What to Put in the Document
Start by identifying both parties by full legal name and address. For individuals, use the name on their government ID. For a business, use its exact registered name, including any “Inc.” or “LLC.” Getting this wrong creates real headaches if you ever need to enforce the agreement. Include the date the contract is made.
The core of the document is what each side is promising. For services, spell out what work will be done, who will do it, what the deliverables look like, and when they’re due. For goods, describe the items in enough detail that there’s no ambiguity about quantity, quality, or specifications. Vague language like “satisfactory results” is an invitation for a fight.
Payment terms should be explicit: the total amount, when payments are due, whether there are milestones or installments, accepted payment methods, and consequences for late payment. If there’s a deposit, say whether it’s refundable and under what conditions.
Termination
Every contract should describe how it ends. Include the duration and what happens when it expires. Address early termination two ways: for cause, which lets one side end the agreement if the other misses deadlines, does shoddy work, or fails to pay; and for convenience, which lets either party walk away for any reason after a specified notice period. Without termination provisions, both parties can end up stuck in an arrangement that no longer works.
Confidentiality
If either side will share sensitive business information, add a confidentiality clause. Define what counts as confidential, spell out how the receiving party must protect it, and set how long the obligation lasts. Terms typically run one to five years, though trade secrets often need indefinite protection. Say what happens when the obligation ends, such as returning or destroying the materials.
Indemnification
An indemnification clause assigns responsibility for certain losses. One party promises to cover the other’s costs if a specific problem comes up. A contractor might agree to cover legal costs if their work infringes on a third party’s intellectual property, for example. These clauses matter most when the work could expose one side to claims from outsiders.
Boilerplate That Does Real Work
The clauses that sit at the end of a contract under “Miscellaneous” or “General Provisions” get skimmed. That’s a mistake. They do heavy lifting when something goes wrong.
- Entire agreement. States that the written contract is the complete deal. Without it, prior emails and conversations could be used to argue the contract means something different.
- Severability. If a court finds one provision unenforceable, this keeps the rest intact. Without it, a single bad clause could theoretically sink the whole contract.
- Governing law. Specifies which state’s laws apply. When the parties are in different states, this avoids an expensive fight over which rules govern a dispute.
- Amendment. Requires any changes to be made in writing and signed by both sides. This reduces the risk that an offhand conversation gets treated as a binding change.
- Force majeure. Excuses performance when extraordinary events beyond either party’s control make it impossible. Natural disasters, wars, pandemics, and government actions are typical triggers. Courts read these clauses narrowly, so list the specific events rather than relying on vague catch-all language. An economic downturn alone generally doesn’t qualify.
- Assignment. Addresses whether either party can transfer their rights or obligations to someone else. If you hired a specific person for their expertise, you probably don’t want them handing the job off to a stranger.
Handling Disputes Before They Happen
The cheapest time to deal with a dispute is before it exists. A dispute resolution clause sets the process both sides will follow when a disagreement comes up.
Mediation is the least adversarial option. A neutral third party helps both sides negotiate but has no power to impose an outcome. The parties keep control, the process wraps up in weeks rather than months, and it preserves an ongoing relationship far better than a courtroom fight.
Arbitration is more formal. An arbitrator hears both sides and issues a binding decision that bypasses the court system. It can be faster than litigation, though arbitrator fees, expert costs, and attorney time still add up. The tradeoff is finality: the arbitrator’s decision is essentially unreviewable. Many commercial contracts include a step clause requiring mediation first, arbitration second.
Your clause should specify the method, the location, who pays the costs, and whether the resolution is binding. Leave this out and any dispute defaults to court, where timelines are unpredictable and costs escalate fast.
You can also decide in advance what a breach will cost. A liquidated damages clause sets a predetermined amount payable if one side fails to perform. It’s enforceable as long as the amount is a reasonable estimate of the anticipated harm and the actual loss would be difficult to calculate. A number that looks like a punishment rather than an estimate will be struck down. Where a breach would cause hard-to-measure losses, this clause saves both sides from proving damages later.
Writing It Clearly
Write in plain language. Legal jargon doesn’t make a contract more enforceable, and it increases the chance someone misunderstands their obligations. If a term has a specific meaning in the agreement, define it in a definitions section at the top and use it consistently.
Organize the document with numbered sections and clear headings. Group related provisions together: payment terms in one place, termination in another. Number every clause so parties can point to specific provisions without confusion. A well-structured contract is easier to read at signing and easier to navigate two years later when everyone is trying to figure out who owes what.
Avoid ambiguity. “Reasonable time,” “best efforts,” and “as needed” mean whatever each party wants them to mean once the relationship sours. Use specific numbers, dates, and measurable standards. Instead of “the contractor will complete the work promptly,” write “the contractor will deliver the finished design files by April 30, 2026.”
Signing It Properly
Every party must sign. Each signature should include the signer’s printed name, title (if signing for a business), and the date. If someone is signing on behalf of a company, confirm they actually have authority to bind that company. A signature from a random employee won’t necessarily hold up.
Electronic signatures carry the same legal weight as ink for most contracts. Federal law prohibits courts from refusing to enforce a contract solely because it was signed electronically.1Office of the Law Revision Counsel. 15 USC 7001 – General Rule of Validity The main exceptions involve wills, family law documents, and certain court orders, which still require traditional signatures in most jurisdictions.
Some contracts need an extra step. Real estate deeds, powers of attorney, and certain sworn documents typically require notarization. A notary public verifies the identity of each signer and confirms they’re signing voluntarily. If you’re unsure whether your contract needs notarization or witnesses, check the requirements for your type of agreement in your state.
Once signed, each party gets a complete copy. Store yours somewhere secure, whether that’s a fireproof safe, cloud storage, or both. You’ll need it if a dispute arises, and you may need to reference it throughout the life of the agreement.
Things That Can Void a Contract Later
Even a properly signed contract with all five elements can be challenged. Knowing these defenses helps you avoid building a contract that won’t hold up.
- Duress. An agreement signed under threats to the signer’s person, family, or property is voidable. Economic pressure can qualify, but only when it rises to wrongful and oppressive conduct.
- Unconscionability. Terms so one-sided they shock the conscience can be struck down, particularly when the disadvantaged party had significantly less bargaining power or sophistication than the party who drafted them.
- Fraud or misrepresentation. If one party lies about a material fact to induce the other to sign, the deceived party can void the contract. The lie has to concern something significant, not a trivial detail.
- Mutual mistake. When both parties share a false belief about a fundamental fact underlying the agreement, either side can seek to void it. A unilateral mistake, where only one party is wrong, is harder to use as a defense.
- Undue influence. Someone in a position of trust or authority pressures another person into an agreement they wouldn’t have entered voluntarily. It shows up most often between caregivers and elderly individuals, attorneys and clients, or family members with unequal power.
The practical takeaway: don’t pressure anyone into signing, don’t misrepresent the facts, and make sure both sides actually understand the terms. A contract signed under bad conditions is worse than no contract, because it creates a false sense of security.
When to Bring in a Lawyer
Simple contracts between two people for straightforward transactions can often be handled without legal counsel. A freelance design agreement, a basic equipment sale, or a short-term service arrangement usually doesn’t require a $400-per-hour review.
Complexity changes the calculus quickly. Commercial real estate leases, business acquisitions, partnership or shareholder agreements, employment contracts with non-compete provisions, and any deal involving intellectual property licensing carry enough risk to justify professional drafting or review. The same goes for any contract where the dollar amount is large enough that a mistake would be genuinely painful. Hiring a lawyer to review a $200,000 construction contract is cheap insurance. Hiring one to draft a $500 lawn care agreement is overkill.
The biggest drafting mistakes usually aren’t the terms people negotiate carefully. They’re the terms people forget to include: what happens if delivery is late, who bears the risk of loss during shipping, whether one party can assign the contract, how disputes get resolved. A lawyer’s value often lies less in what they write and more in what they catch you leaving out.