What Actually Makes a Contract Enforceable? A Plain-English Guide

If you've ever wondered what separates a real contract from a pinky promise, you're not alone. Contract law sounds intimidating, but the core concepts are surprisingly straightforward. Understanding them helps you figure out where your casual agreement stands — and more importantly, what to be aware of.

This is the plain-English version. No Latin phrases, no case citations, no law school prerequisites required.

The Five Essential Elements

For a contract to be legally enforceable, it generally needs all five of these elements. Miss one, and you probably don't have a contract — at least not one a court would back up.

1. Offer

One party proposes specific terms. This needs to be clear enough that someone could say "yes" or "no" to it. "Let's hang out sometime and I'll take care of you" is not an offer in the legal sense. "I'll provide $3,000 per month in exchange for meeting twice per week" is closer to one.

In casual arrangements: Offers are often vague and evolve through conversation rather than being stated formally. That vagueness is one reason courts struggle with these agreements.

2. Acceptance

The other party agrees to the terms. Acceptance must mirror the offer — if someone changes the terms in their acceptance ("I'll do that, but only once a week"), that's actually a counter-offer, not acceptance.

In casual arrangements: Acceptance is usually verbal or implied by conduct. Someone showing up to the first date after discussing terms is generally considered acceptance, but proving the exact terms accepted can be difficult.

3. Consideration

This is the element that trips most people up. Consideration means each party must give up something of value. It's the "what's in it for each of us" element. Money, services, property, or even a promise to do (or not do) something can count.

In casual arrangements: This is the most legally fraught element. Courts may refuse to recognize companionship, affection, or intimacy as valid consideration because of public policy concerns. Financial support in exchange for time together sits in an uncomfortable legal gray area.

4. Capacity

Both parties must have the legal ability to enter a contract. This means they must be:

• Of legal age (18 in most jurisdictions)
• Of sound mind (not impaired by substances, mental illness, or duress)
• Not under undue influence or coercion

In casual arrangements: Power imbalances are common — age gaps, wealth gaps, experience gaps. While these don't automatically negate capacity, they can raise questions about whether consent was truly free and informed.

5. Legality

The purpose of the contract must be legal. You can't enforce a contract for something that violates the law or public policy.

In casual arrangements: This is often the fatal element. Many jurisdictions have laws that make certain personal exchanges legally problematic. Even where no specific law is broken, courts may invoke "public policy" to decline enforcement.

What About Written vs. Verbal Agreements?

A common misconception: contracts have to be in writing. In most jurisdictions, verbal contracts are theoretically enforceable (with some exceptions, like real estate transactions). The problem isn't legality — it's proof. A verbal agreement is only as strong as both parties' willingness to honor it, because proving its exact terms in court is extremely difficult.

For casual arrangements, written terms serve as a reference point even if they're not formally enforceable. See Why Most Casual Agreements Aren't Legally Binding for more on this.

The "Enforceable" Spectrum

Not every agreement is either fully enforceable or completely worthless. Think of it as a spectrum:

Fully enforceable: Formal contracts with all five elements, usually in professional or commercial contexts. Both parties can sue for breach and expect a court to provide a remedy.

Partially enforceable: Some elements of the agreement might hold up. For example, a confidentiality clause in a casual agreement might be enforceable even if the rest of the arrangement isn't. A property agreement might survive even if the companionship terms don't.

Morally binding but not legally enforceable: The agreement is clear and both people committed to it, but a court won't enforce it. This is where most casual arrangements land. The agreement is valuable because both people chose to honor it, not because a court could force them to.

Not even an agreement: Vague understandings, implied expectations, and assumptions. Nothing to enforce because nothing was actually agreed upon. This is what you get when you assume instead of ask.

Practical Takeaways

What this means for your casual arrangement:

1. Don't rely on enforceability. Design your arrangement around trust and clear communication, not the threat of legal action.

2. Write things down anyway. The process of writing and agreeing on terms is valuable in itself. It forces clarity.

3. Keep financial and personal terms separate. If you want any part of your agreement to be potentially enforceable (like a confidentiality clause), it helps to keep it distinct from the personal companionship elements.

4. Watch for unconscionable terms. Even in an informal agreement, terms that are grossly unfair to one party signal a problem — whether or not a court would ever see them.

5. Know when to get professional help. If significant money, property, or life changes are involved, a conversation with a lawyer is worth the investment. See When to Hire a Lawyer.

What Courts Actually Care About

If a dispute from a casual arrangement somehow ended up in court, here's what a judge would likely consider:

• Did both parties enter freely? Any sign of coercion, undue influence, or incapacity weakens enforceability.
• Were the terms clear? Vague or contradictory terms are hard to enforce.
• Is the subject matter legal? The arrangement can't be for an illegal purpose.
• Was there real consideration? Both sides need to have exchanged something of value.
• Is enforcement consistent with public policy? This is the catch-all that kills most casual arrangement enforcement attempts.

The Bottom Line

Understanding what makes a contract enforceable isn't about turning your casual arrangement into a legal document. It's about understanding the framework so you can make informed decisions about what to put in writing, what to keep separate, and when to seek professional advice.

Most casual agreements operate on trust, not law. And that's not a weakness — it's a feature, as long as both people go in with open eyes.

For more on this topic, explore our Enforceability Basics hub.

Disclaimer: This article is for educational purposes only and does not constitute legal advice. Contract law varies by jurisdiction, and specific situations may be governed by different rules. Consult a qualified attorney for advice about your particular circumstances.