Conditionality in contract law is the principle that a party’s duty to perform only becomes enforceable when a specified event occurs. Until that trigger happens, the obligation sits dormant, and if the event never materializes, the duty may never arise at all or may be discharged entirely. The Restatement (Second) of Contracts defines a condition as “an event, not certain to occur, which must occur, unless its non-occurrence is excused, before performance under a contract becomes due.”1Open Casebook. Restatement (Second) of Contracts 224 Understanding which type of condition you’re dealing with can decide whether you walk away from a deal clean or find yourself locked into obligations you never meant to accept.
How a Conditional Obligation Actually Works
An unconditional promise creates an immediate duty. You sign, you owe. A conditional obligation is different: performance cannot become due unless the condition occurs or its non-occurrence is excused, and once the condition can no longer occur, the duty is permanently discharged.1Open Casebook. Restatement (Second) of Contracts 224
One point trips people up constantly. The non-occurrence of a condition is not automatically a breach. If a buyer’s mortgage falls through and the sale collapses, nobody broke a promise. The condition simply didn’t happen. A party only breaches if they had an independent duty to make the condition occur and failed to do so. That distinction decides whether the disappointed party can recover damages or merely walks away empty-handed.
Express Conditions and Constructive Conditions
Not every condition carries the same weight, and the type controls how precisely you have to satisfy it.
An express condition is one the parties wrote into the agreement, usually with language like “provided that,” “on the condition that,” or “subject to.” Because the parties deliberately chose to include it, courts enforce express conditions strictly. If the contract says a buyer must secure financing within 45 days, day 46 is too late. Close enough does not count. Many deals fall apart at exactly this seam: a party substantially meets an express condition but misses a technical detail, and the other side uses the gap to walk.
Constructive conditions are implied by law rather than written into the agreement. Courts read them in to keep the deal fair, and the most important one is that each party’s performance is conditioned on the other party’s performance. Constructive conditions require only substantial performance, not perfection. A contractor who builds a house using a trivially different brand of plumbing pipe has substantially performed even if the work doesn’t match the specifications to the letter. When a court can’t tell whether a term is an express condition or a constructive one, it prefers the reading that reduces the risk of forfeiture for the party who would otherwise lose out.2Open Casebook. Restatement (Second) of Contracts 227
Condition Precedent
A condition precedent is a gate that has to open before any duty to perform is triggered. The classic case is a residential real estate contract where the buyer’s obligation to purchase depends on securing mortgage financing. The contract might specify that the buyer must obtain a written loan commitment for a 30-year fixed-rate mortgage at an interest rate not exceeding a stated cap within 45 days. If the buyer cannot secure that financing despite a genuine effort, the condition fails and the purchase obligation never arises.
Satisfaction Clauses
Some contracts make one party’s duty to pay conditional on personal satisfaction with the other side’s work. If an artist is hired to paint a portrait for $5,000, the client’s obligation to pay might depend on whether they find the finished piece acceptable. Courts split these into two kinds. When the subject matter involves personal taste or artistic judgment, honest dissatisfaction is enough to prevent the condition from being met, even if most people would love the result. When the performance can be measured by objective standards, courts prefer a reading that treats the condition as met if a reasonable person in the same position would be satisfied.3Open Casebook. Restatement (Second) of Contracts 228 Either way, the dissatisfied party has to act in good faith. Claiming dissatisfaction as a pretext to escape a bad bargain won’t hold up.
Notice and Timing
When a condition precedent is satisfied, the benefitting party generally has to tell the other side within the timeframe the contract sets. Failing to communicate fulfillment on time can have the same effect as failing the condition itself: the agreement expires. A buyer who secures financing but neglects to send written notice within the stated deadline may find the deal void. The same logic runs in reverse. If a home inspection turns up defects the buyer can’t accept, written notice to the seller within the inspection period is typically required to preserve the right to walk away.
Condition Subsequent
A condition subsequent runs the other direction. Instead of preventing a duty from arising, it terminates a duty that already exists. Both parties are currently bound, and they stay bound unless a specified event occurs to end the obligation.
A 30-day return policy is the simplest example. The consumer owns the product and the merchant has the payment, and returning the item within the window cancels both sides’ rights. Corporate agreements use similar structures. If a shareholder violates a non-compete, the company may have a pre-existing right to repurchase their shares at a set price, and the violation triggers the end of the shareholder’s right to hold equity. These clauses give parties a defined exit ramp without needing a court to dissolve the arrangement.
Who Has to Prove What
The distinction between precedent and subsequent has a real consequence in court. The party seeking to enforce a contract generally has to prove all conditions precedent were met. The party trying to escape an obligation has to prove that a condition subsequent occurred and discharged their duty. In insurance disputes, this plays out constantly. An insurer arguing that a policy exclusion applies has to prove the triggering event, rather than forcing the policyholder to prove the exclusion doesn’t apply.
Concurrent Conditions
Concurrent conditions require both parties to perform at the same time. When performances can be rendered simultaneously, they are due simultaneously unless the contract or circumstances indicate otherwise.4Open Casebook. Restatement (2d) Sections on Conditions Cash-on-delivery is the textbook case: goods and payment change hands at the same moment.
Real estate closings work the same way. The lender transfers the borrowed funds to the settlement agent, who delivers the purchase price to the seller, and the seller signs the deed transferring ownership to the buyer.5Consumer Financial Protection Bureau. What Can I Expect in the Mortgage Closing Process If the buyer shows up with a certified check but the seller has no signed deed, the seller has failed the concurrent condition and the buyer’s duty to pay is suspended. Neither side is exposed by performing first.
To claim the other party breached a concurrent condition, you have to show you tendered your own performance: that you were ready, willing, and able to complete your side immediately. A buyer who arrives without funds can’t complain that the seller didn’t produce a deed. Under the Uniform Commercial Code, tender of payment by the buyer is a condition to the seller’s duty to tender and complete delivery, and the reverse holds as well. The symmetry is the whole point.
When Conditions Are Waived or Excused
Conditions don’t always play out the way the contract describes. The law recognizes several situations where a condition is waived or excused, and the obligation becomes enforceable even though the triggering event never occurred.
Voluntary Waiver
A party who benefits from a condition can choose to give it up. A homebuyer who included a financing contingency can waive it and proceed with cash. Well-drafted contracts require waivers to be in writing and signed by the waiving party, because oral waivers produce disputes about what was actually agreed. Waiving one condition doesn’t waive others. Forgiving a late delivery once doesn’t surrender your right to demand on-time delivery going forward.
Whether a waiver can be pulled back depends on the circumstances. If the other party has materially changed position in reliance on the waiver, retracting it would be inequitable and courts will hold the waiving party to it. If no reliance has occurred, the waiving party can generally reinstate the condition by giving reasonable notice.
Excuse by Prevention
A party who causes a condition to fail cannot then use that failure to escape their own obligations. If a contractor refuses to give a subcontractor access to the work site, the contractor can’t later argue the subcontractor failed to finish on time. Where a party’s breach by non-performance materially contributes to the non-occurrence of a condition of one of their own duties, the non-occurrence is excused.6Open Casebook. Restatement (Second) of Contracts 245 The rule is intuitive, and yet it comes up in litigation constantly, because the interfering party rarely sees their own behavior as the problem.
Excuse to Avoid Forfeiture
Courts also have the power to excuse a condition when enforcing it strictly would cause disproportionate forfeiture. If a party has substantially performed and would lose the entire benefit of the contract over a technical failure to satisfy an express condition, a court may excuse the condition, provided the condition wasn’t a material part of what the parties bargained for.7Open Casebook. Restatement (Second) of Contracts 229 Courts use this power sparingly. It exists as a safety valve for cases where rigid enforcement would produce an outcome grossly out of proportion to the breach.