Promissory estoppel and restitution

Promissory estoppel and restitution

Published September 28, 2026

Promissory estoppel and restitution

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The Reliance Trigger: When a Promise Becomes Enforceable

Promissory estoppel enforces a promise when reliance, rather than a bargained-for exchange, makes nonenforcement unjust. Apply Restatement (Second) of Contracts §90 in this order:

  1. Promise: The promisor made a manifestation of commitment, not merely a prediction, opinion, puffery, or preliminary negotiation. A sufficiently definite statement of intention may constitute a promise, depending on how it would reasonably be understood.

  2. Expected inducement: The promisor should reasonably have expected the promise to induce action or forbearance by the promisee or a third person.

  3. Actual reliance: The promise did induce action or forbearance. The claimant must connect the change in position to the promise; reliance that occurred before the promise does not qualify.

  4. Reasonableness and detriment: The reliance was reasonable under the circumstances and constituted action or forbearance that caused a detriment or otherwise changed the claimant’s position. Spending money, giving up employment, moving, beginning performance, or forbearing from a legal right can qualify. The promisor need not receive a benefit.

  5. Injustice: Injustice can be avoided only by enforcing the promise. A breach alone is not enough; the court considers the seriousness of the reliance, the promisor’s conduct, the clarity of the promise, and whether another remedy adequately addresses the harm.

The promise need not have been supported by consideration, and the claimant need not prove that the promise would have been an enforceable offer or contract. But promissory estoppel is not a substitute for identifying the promisor’s actual words. A vague hope that “things will work out” does not become a promise merely because someone relies on it.

Timing matters. The promisor’s expectation is judged when the promise was made; actual causation and reasonableness are judged from what happened afterward. Reliance must be sufficiently connected to the promise. If an employee quits before the employer makes the promised offer, the quitting cannot be reliance on that offer. If the employee quits after the promise but for an unrelated reason, actual inducement is missing.

The remedy is deliberately flexible. Under §90, the promise is binding only to the extent justice requires. The court may award reliance damages, enforce the promise partially, or provide another limited remedy. Full expectation damages are not automatic. A claimant who spends $4,000 in reliance does not necessarily receive the promised $50,000, particularly where awarding the full amount would overcompensate the claimant.

Promissory estoppel is also distinct from reliance that makes an offer irrevocable; the sibling chapter on acceptance and irrevocable offers owns that revocation question. Here the question is whether reliance makes the underlying promise enforceable. Under UCC §1-103(b), common-law principles supplement Article 2 unless displaced, so §90 can matter in a goods setting, but Article 2’s Statute of Frauds and its specific exceptions remain separate issues. This is closed-book-state §90’s five-part application and its limited-remedy rule without prompting.

The Benefit-Based Obligation: Restitution Without a Bargain

Restitution enforces a benefit-based obligation. The central question is not “Was there a promise that induced reliance?” but “Would the recipient be unjustly enriched by retaining a benefit received at the claimant’s expense?”

For implied-in-law restitution, analyze these requirements:

  1. Benefit: The claimant conferred a measurable benefit on the recipient, such as money, services, goods, or necessary protection of property.

  2. At the claimant’s expense: The benefit came from the claimant or caused the claimant to incur the relevant cost.

  3. Knowledge or acceptance: The recipient knew of and accepted the benefit, or the circumstances make the benefit chargeable despite the recipient’s inability to consent.

  4. Unjust retention: Retaining the benefit without payment would be inequitable in the circumstances.

  5. No gift or officious intervention: The claimant did not intend to confer a gift and did not force an unwanted benefit on the recipient for the claimant’s own purposes.

A request for the service strongly supports restitution because it shows that the recipient wanted the benefit. A recipient who knowingly accepts a service and has an opportunity to reject it may also be liable even if the price was never agreed. By contrast, the officious intermeddler rule denies recovery when a person unilaterally provides an unwanted benefit, especially to create a payment claim or pursue the person’s own objectives.

The principal exception to the no-request rule is an emergency. A person who supplies necessary services to protect another’s person or property when the recipient cannot consent may recover the reasonable value of those services, provided the services were necessary and the claimant was not acting as a volunteer. A mistaken payment is another important setting: the recipient generally must return money paid by mistake, subject to defenses such as a good-faith change of position.

Restitution measures the recipient’s enrichment, not the claimant’s expected profit and not the value of a promise. If a contractor’s unsolicited work increases property value by $2,000, the contractor ordinarily cannot recover a $10,000 hoped-for fee. If the recipient was not enriched, or if the benefit was intended as a gift, restitution fails. If the recipient changed position in good faith before learning of a mistaken transfer, the amount recoverable may be reduced to prevent unfairness.

A related doctrine is Restatement (Second) of Contracts §86, promise for benefit received. It concerns a later promise made in recognition of a benefit previously received by the promisor from the promisee. The promise may be binding to the extent necessary to prevent injustice even though the earlier benefit was not bargained for. Section 86 does not apply when the benefit was conferred as a gift or when the promisor was not unjustly enriched. If the promised performance is disproportionate to the benefit received, the promise is not binding to the extent of that disproportion.

Keep the two restitution routes separate:

  • Pure restitution: No later promise is necessary. The claimant seeks the value of an unjustly retained benefit.

  • Section 86: A later promise exists, but its enforcement is limited by the benefit and by what preventing injustice requires.

That distinction prevents a common error: treating every promise made after a benefit as enforceable for its full stated amount. A later promise may be evidence of the enrichment, but §86 does not automatically convert a past benefit into a full contract claim. The consideration chapter’s treatment of past consideration and moral obligation is the boundary; §86 asks specifically about benefit received and unjust enrichment.

Restitution may also restore benefits transferred under an invalid or unenforceable agreement. That remedy does not enforce the failed bargain or award expected profits; it returns or values what the recipient actually received. In a goods transaction, first determine whether Article 2 supplies an enforceable contract or a specific statutory remedy. If it does, use that governing rule rather than quasi-contract for the same performance. If no contract governs, common-law restitution may supplement Article 2 under §1-103(b), unless displaced.

QuestionPromissory estoppelImplied-in-law restitutionRestitution-based promise
Source of obligationPromise plus relianceBenefit plus unjust retentionLater promise recognizing prior benefit
Required claimant showingExpected and actual reasonable relianceBenefit conferred at claimant’s expenseBenefit received by promisor from promisee
Main near missNo actual promise or no induced relianceGift or officious intermeddlingBenefit was a gift or promise is disproportionate
Usual measureReliance or limited enforcementValue of recipient’s enrichmentAmount necessary to prevent injustice
What is not automaticFull expectation damagesPromised price or claimant’s hoped-for profitFull amount of later promise

The Boundary in Action: One Promise With No Benefit

An aunt told her niece, “I will give you $20,000 for your first year of nursing school. This is a gift, not payment for anything you do.”
The aunt knew the niece relied on the promise. The niece rejected a paid summer internship, enrolled in the program, and paid a nonrefundable $8,000 tuition deposit.
Before classes began, the aunt withdrew the promise. The niece brings an action to recover.

Practice

Which is the niece’s strongest basis for recovery?

The recurring errors are these:

  • Treating the niece’s enrollment as consideration despite the aunt’s express statement that the promise was not an exchange.

  • Calling the tuition payment restitution when the aunt received no benefit from it.

  • Awarding the full $20,000 automatically instead of applying §90’s limited-remedy principle.

  • Seeking payment for unsolicited lawn mowing when the homeowner neither requested nor knowingly accepted the service.

  • Using restitution to enforce the promised price of goods when an Article 2 contract or specific UCC remedy controls.

Three Pressure Tests: Promise, Past Benefit, and Unrequested Work

Practice

A company president told Dana, “I will pay your $15,000 graduate-school tuition. I am offering this as support, not in exchange for services.” Relying on the statement, Dana declined a job and paid a nonrefundable tuition deposit. The president later withdrew the promise. What is Dana’s strongest claim?

After a storm, Mara repaired her neighbor’s broken gate without being asked. The neighbor saw the completed repair, kept the improved gate, and then promised to pay Mara $700. The reasonable value of the benefit was $400, and the neighbor later refused to pay. Which result is best?

A landscaper mistakenly mowed a homeowner’s lawn while the homeowner was away. The landscaper was trying to advertise the business, the homeowner never requested the work, and the homeowner did not know about it until it was finished. May the landscaper recover the usual fee in restitution?

High-Yield Points - ⚡ Biggest Takeaways

Use §90 only when a promise actually induced reasonable reliance and injustice requires enforcement. Restitution follows an unjust benefit; it does not award the promise’s value or compensate an officious volunteer. A later promise for a past benefit is §86: enforce only what preventing injustice requires.

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Practice Questions: Promissory estoppel and restitution

  1. 1. A collector signed a written offer promising to sell a rare watch to a buyer for $18,000. The writing stated, "I will keep this offer open until Friday at 5:00 p.m." The buyer gave no consideration for that promise. On Thursday morning, a reliable mutual acquaintance told the buyer that the collector had sold the watch to another person. The collector had not directly communicated with the buyer. On Thursday afternoon, the buyer emailed an acceptance, which the collector received immediately. The transaction is a sale of goods, but the collector is not a merchant in watches. Which of the following best states whether a contract was formed?

    • A. A contract was formed because a signed promise to keep an offer open creates an option without consideration.
    • B. A contract was formed because only a revocation communicated directly by the offeror can terminate an offer.
    • C. No contract was formed because reliable information of the sale indirectly revoked the offer before acceptance.
    • D. No contract was formed because an offer to sell goods may be accepted only by tendering payment.
    Show answer

    Answer: C. No contract was formed because reliable information of the sale indirectly revoked the offer before acceptance.

    No contract was formed because reliable information of the sale indirectly revoked the offer before acceptance. - The reliable mutual acquaintance’s report that the collector had sold the watch gave the buyer notice of definite action inconsistent with the offer, indirectly revoking it on Thursday morning. - The buyer’s email arrived Thursday afternoon, after the offer had been revoked, so it could not form a contract. A contract was formed because a signed promise to keep an offer open creates an option without consideration. - The collector’s promise to keep the offer open until Friday lacked the consideration needed to create an option contract. - A signed offer to sell goods can be irrevocable without consideration under the merchant firm-offer rule, but the collector was not a merchant in watches. A contract was formed because only a revocation communicated directly by the offeror can terminate an offer. - Revocation need not come directly from the collector when the buyer learns from a reliable source that the collector has sold the watch. - That information reached the buyer Thursday morning, before the buyer emailed an acceptance. No contract was formed because an offer to sell goods may be accepted only by tendering payment. - The written offer did not require tender of the $18,000 as the method of acceptance; an emailed acceptance could ordinarily suffice. - No contract formed because the offer had already been indirectly revoked, not because the buyer failed to tender payment.

  2. 2.

    • 3. Using only the supplied client file and legal resources, prepare an advisory letter to the client assessing whether the client can compel the seller to complete the land sale. Explain the writing requirement, the financing condition, available remedies, litigation risks, and the most appropriate immediate next step.

      • 4. Using only the supplied file and legal resources, prepare a confidential negotiation memorandum for the supervising attorney and client. Evaluate whether BrightLeaf could assign royalty-payment rights or delegate editing and marketing duties to PageTurn Media, whether Ortiz must accept PageTurn's performance, and whether BrightLeaf's communications amount to repudiation. Recommend negotiation objectives, concessions, information requests, and protective terms that preserve the book's launch while addressing Ortiz's financial and performance concerns.

        • 5. Using only the supplied file and legal resources, draft a persuasive settlement letter to counsel for Metro Packaging concerning FreshField Foods' purchase of 10,000 glass jars. State FreshField's supportable damages demand, explain which claimed losses are recoverable or vulnerable, address Metro's arguments about the limitation clause, foreseeability, certainty, and mitigation, and propose a commercially reasonable settlement structure. Do not threaten unsupported remedies or rely on outside law. The client wants prompt reimbursement while preserving the supplier relationship if adequate quality controls are adopted. Include a concise factual introduction, legal analysis, quantified demand, response to counterarguments, and a practical proposal for payment and future performance.

          • 6.

            • 7. On March 1, a machine manufacturer sent a signed email to a retailer offering to sell 20 standard generators for $8,000 each. The email stated, "This offer will remain open through April 15." Both parties regularly deal in generators. The retailer gave no consideration for the promise to keep the offer open. On March 20, the manufacturer emailed, "Market prices have increased, so I withdraw my offer." The retailer received that message immediately. On March 25, the retailer emailed an unconditional acceptance of the March 1 terms. The manufacturer refused to deliver, asserting that the offer had been revoked. The retailer asks whether an enforceable contract was formed. Which of the following is the most appropriate advice?

              • A. A contract was formed because the signed merchant's assurance made the offer irrevocable when the retailer accepted within the stated period.
              • B. No contract was formed because an offeror may revoke any unaccepted offer unless the offeree paid consideration for an option.
              • C. No contract was formed because the retailer did not accept before the manufacturer communicated its attempted revocation.
              • D. A contract was formed only if the retailer can prove foreseeable reliance on the promise that the offer would remain open.
              Show answer

              Answer: A. A contract was formed because the signed merchant's assurance made the offer irrevocable when the retailer accepted within the stated period.

              A contract was formed because the signed merchant's assurance made the offer irrevocable when the retailer accepted within the stated period. - Generators are goods, and the manufacturer’s signed email assuring that the offer would remain open through April 15 was a merchant’s firm offer under UCC Article 2. - The March 20 withdrawal was ineffective during that period, so the retailer’s unconditional March 25 acceptance formed a contract for 20 generators at $8,000 each. No contract was formed because an offeror may revoke any unaccepted offer unless the offeree paid consideration for an option. - Although an ordinary offer generally can be revoked before acceptance, UCC Article 2 makes a qualifying merchant’s firm offer irrevocable without consideration. - The retailer’s failure to pay for an option therefore did not permit withdrawal of the manufacturer’s signed offer before April 15. No contract was formed because the retailer did not accept before the manufacturer communicated its attempted revocation. - The retailer received the withdrawal on March 20 and accepted on March 25, but the signed assurance protected the offer through April 15. - Because the attempted revocation was ineffective, acceptance did not have to precede the March 20 message. A contract was formed only if the retailer can prove foreseeable reliance on the promise that the offer would remain open. - Reliance is not required to enforce a merchant’s firm offer satisfying UCC Article 2’s requirements. - The manufacturer’s signed assurance kept the offer open, and the retailer accepted its terms on March 25 without needing to prove any change of position.

            Flashcards: Promissory estoppel and restitution

            1. 1. What is the common-law mirror-image rule, and what is the effect of a nonconforming response to an offer?

              Show answer

              Under the majority common-law rule, acceptance must match the offer’s terms exactly; a response adding or changing terms is generally a counteroffer, not an acceptance. A mere inquiry or request that does not condition assent on the new term is not a counteroffer.

            2. 2. When does an acceptance become effective under the mailbox rule, and what are its principal exceptions?

              Show answer

              Under the majority mailbox rule, an acceptance is effective when properly dispatched, unless the offer requires receipt, the acceptance is sent after a prior rejection, or the offer is an option contract. For an option contract, acceptance generally becomes effective only upon receipt.

            3. 3. What is the preexisting-duty rule for consideration?

              Show answer

              A promise to perform a duty the promisee already owes the promisor is not new consideration because it adds no legal detriment or benefit. The rule generally does not apply when the duty is owed to a third party or when unforeseen circumstances support a fair modification under the applicable law.

            4. 4. What is required to accept an offer for a unilateral contract under the Restatement majority rule?

              Show answer

              The offeree must complete the requested performance; beginning performance creates an option contract under Restatement § 45, but it does not itself complete acceptance or form the underlying contract.

            5. 5. What standard determines whether a party manifested intent to enter a contract?

              Show answer

              The majority rule applies an objective standard: intent is determined by the party’s outward words and conduct as reasonably understood by the other party, not by undisclosed intent.

            6. 6. What makes an offer sufficiently definite under the common law?

              Show answer

              The offer must identify the parties, subject matter, and essential terms with enough certainty for a court to determine breach and provide a remedy; typically, price, quantity, and time are required when material.

            7. 7. When can silence operate as acceptance of an offer?

              Show answer

              Silence ordinarily is not acceptance, but it may operate as acceptance when the offeree takes the benefit of offered services with a reasonable opportunity to reject, the parties’ prior dealings establish that silence means assent, or the offeree indicates that silence will constitute acceptance and intends that result.

            8. 8. How are advertisements and other general solicitations ordinarily treated in contract formation?

              Show answer

              Under the majority rule, they are invitations to make offers rather than offers because they usually lack commitment and definite terms. An advertisement can be an offer if it is clear, definite, explicit, and leaves nothing open for negotiation.

            9. 9. Why is an illusory promise insufficient consideration?

              Show answer

              A promise is illusory when it does not actually bind the promisor, such as a promise to buy only if the promisor chooses to do so. Because no legal detriment is exchanged, it cannot serve as consideration for the other party’s promise.

            10. 10. What events terminate the power of acceptance before acceptance occurs?

              Show answer

              Under the majority rule, the power of acceptance ends by rejection or counteroffer, lapse of the stated or reasonable time, revocation communicated to the offeree, or death or incapacity of either party.

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