What consideration is
Consideration is the thing that makes a promise legally enforceable: a bargained-for exchange in which each side gives up something of legal value. Without consideration (or a substitute for it), a promise is generally just a gift promise, and gift promises aren't enforceable contracts.
The modern definition comes from Restatement (Second) of Contracts §71: a performance or return promise is consideration if it is "bargained for" — meaning it is sought by the promisor in exchange for the promise and given by the promisee in exchange for that promise. The key words are bargained for and exchange.
"Legal value" is broad. It can be a benefit to the promisor or a detriment to the promisee — including giving up a legal right you were free to exercise. The point isn't who comes out ahead; it's that each side incurred something in exchange for the other's promise.
The classic case: forbearance counts
Hamer v. Sidway is the standard illustration. An uncle promised his nephew money if the nephew refrained from drinking, smoking, and gambling until he turned 21. The nephew did, then the estate refused to pay, arguing the nephew suffered no harm — he was better off.
The court held there was valid consideration. The nephew gave up legal rights he was otherwise free to exercise, and that forbearance was bargained for in exchange for the promise. Whether the nephew "benefited" is irrelevant; surrendering a legal freedom at the promisor's request is legal detriment, and that's consideration.
The lesson 1L exams test: consideration doesn't require a tangible loss. A promise to not do something you're legally entitled to do — given in exchange for the other side's promise — is enough.
What is NOT consideration
A large share of Contracts issues come from recognizing when something looks like consideration but isn't. These are the recurring exam traps.
| Not consideration | Why |
|---|---|
| Past consideration | Something already done can't be "bargained for" now — there's no exchange |
| Gift promises | No return promise or performance is sought in exchange |
| Illusory promises | A "promise" that doesn't actually commit the promisor to anything |
| Pre-existing duty | Promising to do what you're already legally bound to do gives nothing new |
| Moral obligation alone | A sense of duty, without a bargained exchange, generally isn't enough |
Note also what doesn't matter: adequacy. Courts generally won't weigh whether the exchange was a good deal — a peppercorn can be consideration. The question is whether there was a bargained-for exchange at all, not whether it was fair.
Promissory estoppel: the backup when consideration is missing
Sometimes a promise lacks consideration but someone reasonably relied on it and got hurt. Promissory estoppel lets a court enforce such a promise to avoid injustice. It's a substitute for consideration, not a type of it.
Restatement (Second) §90 sets out the elements: (1) a promise the promisor should reasonably expect to induce action or forbearance; (2) the promise does induce such action or forbearance; (3) the reliance is reasonable and detrimental; and (4) injustice can be avoided only by enforcing the promise. Courts may limit the remedy "as justice requires," sometimes to reliance damages rather than full expectation.
| Consideration | Promissory estoppel (§90) |
|---|---|
| Bargained-for exchange | No bargain — based on reliance |
| Enforces because a deal was struck | Enforces to prevent injustice from reliance |
| Remedy: usually expectation | Remedy may be limited to reliance "as justice requires" |
The common mistake: confusing adequacy with the existence of a bargain
The most frequent error is arguing that there's no consideration because the exchange was lopsided. Courts don't police adequacy — a token amount can support a contract. The real question is whether the thing was bargained for in exchange for the promise, not whether the trade was fair.
A second mistake is treating promissory estoppel as if it always produces full contract damages. Section 90 expressly allows a court to limit the remedy as justice requires, which often means reliance-based recovery (what the plaintiff lost by relying) rather than the full benefit of the bargain.
Finally, watch the pre-existing duty rule. Promising to do something you're already obligated to do isn't new consideration — a classic trap when parties try to modify a contract by promising the same performance for more money. Look for whether anything new was given.
Frequently asked questions
What is consideration in contract law?
Consideration is a bargained-for exchange in which each side gives something of legal value — a benefit to one party or a legal detriment to the other. Under Restatement (Second) §71, a performance or return promise counts as consideration when it's sought by the promisor in exchange for the promise and given in exchange for it.
Does the exchange have to be fair to be consideration?
No. Courts generally don't examine the adequacy of consideration — even a token amount can be enough. The question is whether there was a genuine bargained-for exchange, not whether the parties struck an equal or fair deal.
What are the elements of promissory estoppel?
Under Restatement (Second) §90: a promise the promisor should reasonably expect to induce reliance; actual action or forbearance in reliance; reasonable and detrimental reliance; and injustice that can be avoided only by enforcing the promise. The remedy may be limited as justice requires, sometimes to reliance damages.
What is the pre-existing duty rule?
Promising to do something you're already legally obligated to do isn't valid consideration, because you're giving nothing new. It commonly appears when a party tries to demand more money for the same performance already owed under an existing contract.
Related Verbloom guides
Sources
Want 1L doctrine to finally click?
Verbloom breaks down the law school concepts that confuse first-years — like Civil Procedure — into short, plain-English lessons and practice built around how the rules actually work.