The three requirements of consideration in contract law are that the exchange be bargained for, that what each side gives up carries legal value, and that the exchange is happening now or promised for the future rather than being based on something already done. Miss any one of them and the deal is just a promise with no legal teeth.
Bargained-For Exchange
Each side’s promise or action has to be given in exchange for the other’s. The Restatement (Second) of Contracts puts it this way: a performance or return promise is bargained for when the promisor seeks it in exchange for the promise, and the other side gives it for that reason.1Open Casebook. Restatement Second Contracts 71 – Consideration You agree to pay $100 because the seller agrees to hand over the bicycle, and the seller agrees to hand over the bicycle because you agree to pay $100. Each commitment motivates the other.
This reciprocal motivation is what separates a contract from a gift. A promise to give someone a car with nothing expected in return is gratuitous, and the recipient cannot force the giver to follow through. The Restatement is explicit: a promise to make a gift of $10, even one that causes the recipient to spend money in reliance, lacks consideration.2Open Casebook. Restatement Second of Contracts 71
“Bargained for” doesn’t require haggling. A homeowner posts a flyer offering $50 to anyone who mows the lawn, a landscaper shows up and agrees, and nobody negotiated a thing. The offer still induced the promise to mow, and the promise to mow induced the commitment to pay. That is enough.
Legal Value on Both Sides
Whatever each party exchanges has to carry legal value. In practice, that means one side either takes on an obligation they didn’t previously have (a legal detriment) or gains something they weren’t otherwise entitled to (a legal benefit). Money is not required. Services, goods, a promise to do something, or a promise to stop doing something all qualify. The Restatement lists an act, a forbearance, or the creation, modification, or ending of a legal relationship as the kinds of performance that count.1Open Casebook. Restatement Second Contracts 71 – Consideration
Forbearance is worth pausing on. Agreeing not to do something you have every right to do is valid consideration, because you’re giving up a legal right. Settling a lawsuit by promising not to pursue your claim in return for a payment is a legal detriment. The textbook example involves an uncle who promised his nephew money if the nephew stopped drinking and smoking until age 21; giving up those legal rights was valid consideration even though quitting was arguably good for him.3Legal Information Institute. Consideration
Adequacy Does Not Matter
Courts care whether consideration exists, not whether the trade was fair. As long as something of legal value changes hands, a judge won’t second-guess a lopsided bargain. Selling a painting worth thousands for a single dollar can be valid consideration, so long as the exchange was genuinely bargained for.4Open Casebook. Restatement Second of Contracts 79
A wildly imbalanced deal can still draw scrutiny, but on different grounds. If a house “sells” for $1 with no plausible reason for the imbalance, a court might examine whether fraud, duress, or a failure of genuine bargaining was at work. The consideration requirement itself is satisfied as long as something real was exchanged.3Legal Information Institute. Consideration
Not Past Consideration
Consideration has to be part of the current deal or promised for the future. Something a person already did before any agreement existed cannot serve as consideration, because the earlier act wasn’t motivated by the later promise. This is the past consideration rule, and it trips people up more than the other two requirements combined.
Your neighbor helps you move furniture over the weekend as a favor, no strings attached. Afterward, feeling grateful, you promise to pay $200. That promise is unenforceable. Your neighbor didn’t haul boxes because you promised to pay; the labor happened before the promise existed, so it couldn’t have been induced by it.3Legal Information Institute. Consideration The whole point of a bargained-for exchange is mutual inducement, and a promise that doesn’t yet exist can’t induce anything.
Future consideration is fine. Hire a painter to paint your house next month and promise to pay on completion, and the painter’s future performance and your future payment are both valid consideration. Who performs first doesn’t matter, as long as the exchange is part of the same agreement.3Legal Information Institute. Consideration
The Material Benefit Exception
The past consideration rule has a narrow exception. Under the Restatement (Second) of Contracts, a promise made in recognition of a benefit the promisor already received can be binding to the extent necessary to prevent injustice.5Open Casebook. Restatement Second Contracts 86 – Promissory Restitution The exception doesn’t apply if the earlier benefit was a gift, or if the promised payment is wildly out of proportion to what was received. If someone saved your life and you later promised to pay them, a court might enforce that promise even though the rescue came first.
What Can Still Sink a Deal That Looks Like It Has Consideration
Even when all three boxes seem checked, two problems regularly undo the consideration analysis.
Illusory Promises
A promise that doesn’t actually commit you to anything isn’t real consideration. If one side can walk away at any time for any reason, or the obligation is so vague it imposes nothing, the promise is illusory and the agreement is unenforceable.6Legal Information Institute. Illusory Promise Agreeing to buy goods “if I feel like it” binds no one, because the promise rides entirely on the promisor’s whim. Unrestricted cancellation clauses create the same problem. The usual fix is to tie the obligation to something outside the promisor’s pure discretion, like a requirements contract where actual business needs drive the quantity.
The Pre-Existing Duty Rule
If you’re already legally required to do something, promising to do that same thing again isn’t new consideration. This comes up most often when parties try to modify an existing contract. A contractor hired to remodel your kitchen for $20,000 who demands $25,000 halfway through to finish the same job hasn’t promised anything new; the contractor was already obligated to complete the work, and the modification may be unenforceable.7Legal Information Institute. Pre-Existing Duty Doctrine
Contracts for the sale of goods are different. Under the Uniform Commercial Code, an agreement modifying a sale-of-goods contract needs no new consideration to be binding.8Legal Information Institute. UCC 2-209 – Modification, Rescission and Waiver If you and a supplier agree to change the price or delivery date on a shipment of materials, that modification can stick without fresh consideration, as long as both sides are acting in good faith. The split between common law contracts (services, real estate) and UCC-governed contracts (goods) catches people mid-deal who assume the same rules apply across the board.
When a Promise Without Consideration Is Still Enforced
A promise that fails the consideration test isn’t always dead. Promissory estoppel can enforce a clear promise where the person making it should have expected reliance, the other side actually relied, and refusing enforcement would be unjust.9Legal Information Institute. Promissory Estoppel Courts treat it as an equitable backup, and damages are often limited to what fairness requires rather than the full value of the bargain. If a deal matters, the safer route is making sure valid consideration supports it from the start.