Unjust Enrichment and Quantum Meruit in California Business Disputes

Last updated: November 2026

Quantum meruit is a California claim for the reasonable value of services or goods provided to someone who accepted them under circumstances showing both sides expected payment. Unjust enrichment is the broader principle behind it: a party that has received a benefit it cannot fairly keep must restore it or pay for it. Neither requires an enforceable contract, which is why both appear when a deal was never signed or is unenforceable. Kolmogorov Law, P.C. brings and defends these claims for businesses in Orange County, Los Angeles, and across California.

Call (909) 235-6116 or contact us online to discuss work your business did without being paid, or a claim that your business was unjustly enriched.

What quantum meruit is

The phrase means "as much as he deserved." The law implies a promise to pay for services performed under circumstances showing they were not rendered gratuitously. To recover, a party need not prove the existence of a contract, but it must show that the services were rendered under some understanding or expectation of both parties that compensation would be made. (Huskinson & Brown v. Wolf (2004) 32 Cal.4th 453, 458, citing Maglica v. Maglica (1998) 66 Cal.App.4th 442, 449.)

Two elements do the work. First, the plaintiff provided something of value. Second, the defendant accepted it knowing, or in circumstances where it should have known, that the plaintiff expected to be paid. A vendor that ships product a customer ordered by phone and uses has a claim. A friend who helps paint an office as a favor does not.

Quantum meruit is pleaded as a common count, and it is usually pleaded alongside breach of contract. If the contract claim fails because the agreement was never finalized or is unenforceable, the common count often survives.

What unjust enrichment in California adds

Unjust enrichment is the principle, not a separate statute. California courts disagree about whether it is a standalone cause of action or a theory of recovery that supports restitution. The safer practice is to plead the underlying claim (quantum meruit, money had and received, constructive trust) rather than rely on the label.

The constructive trust is the most powerful form. A person who gains a thing by fraud, accident, mistake, undue influence, violation of a trust, or other wrongful act is an involuntary trustee of that thing for the benefit of the person who would otherwise have had it. (Civ. Code, § 2224.) That remedy reaches the specific asset, including what it was turned into, rather than just a money judgment.

How recovery is measured

The measure of recovery in quantum meruit is the reasonable value of the services rendered, provided they were of direct benefit to the defendant. (Maglica, supra, 66 Cal.App.4th at p. 449.) The benefit is a threshold requirement, not the yardstick. The court in Maglica found error where the jury was told it could measure the plaintiff's services by the value by which the defendant's business had benefited from them.

For business plaintiffs the practical meaning is this: prove the going rate. Hourly rates for the kind of work, invoices from comparable vendors, and your own standard pricing are the evidence. What the defendant later earned from your work is usually not.

The burden of proving value rests on the party seeking it. A plaintiff with no time records, no rate card, and no comparable invoices will have trouble even if liability is clear.

When the claim is barred

Three bars come up repeatedly.

The first is an express contract on the same subject. Where a valid contract fixes the price, the plaintiff is held to it and cannot use quantum meruit to get more. The claim is for situations where no enforceable agreement covers the work.

The second is illegality. An unlicensed contractor generally cannot recover in any action for work requiring a license, and quantum meruit does not rescue the claim. (Bus. & Prof. Code, § 7031, subd. (a).) Our unlicensed contractor page covers that statute.

The third is time. A quantum meruit claim is an obligation not founded on a writing, so it generally carries a two-year limitations period. (Code Civ. Proc., § 339, subd. 1.) The clock usually starts when the services are completed or the last payment is refused, which can be earlier than a plaintiff expects. Our statutes of limitations guide lists the other periods.

How these claims come up for business owners

A software developer builds a custom platform for a client over eight months while the master services agreement sits unsigned in a lawyer's inbox. The client launches the platform and stops paying. No contract, but a clear expectation of payment and an accepted benefit. The developer sues in quantum meruit for the reasonable value of the development work.

A supplier delivers an extra production run after a buyer's email says "send what you have, we'll sort out pricing." The buyer resells the goods and refuses to pay. Our unpaid invoices page covers the collection side; the common count supplies the theory when the price was never fixed.

Defending an unjust enrichment claim

The defense usually starts by looking for a contract. If one exists and covers the subject, the plaintiff is confined to it. If the contract fixes a price the plaintiff already received, the claim ends there.

The next question is expectation. Work done on speculation, as a pitch, or to win future business is not done with an expectation of payment. The emails from the time usually settle this.

Then value. A defendant who concedes some benefit can still contest the number, and plaintiffs who inflate the rate or claim hours they cannot document lose credibility on everything else.

Finally, timing. Two years is short, and these claims are often brought late because the plaintiff spent a year hoping to be paid.

What we do, and where these cases are heard

We decide which theories to plead (breach of contract, promissory estoppel, quantum meruit, constructive trust), assemble the evidence of value, and pursue or defend the claim. Where a contract was induced by fraud, we consider rescission with restitution as an alternative.

These cases are heard in the Superior Court: the Central Justice Center in Santa Ana for Orange County and the Stanley Mosk Courthouse for Los Angeles, with the Central District of California handling matters with federal jurisdiction. Our breach of contract practice page describes the broader work.

What to bring to the first meeting

Bring the drafts of any agreement and the emails and texts showing what was requested and delivered. Add time or delivery records, your rate card or comparable pricing, invoices sent and any partial payments, and the date the other side last refused a demand.

Frequently asked questions

What is quantum meruit in California?

Quantum meruit is a claim for the reasonable value of services or goods provided to a party who accepted them when both sides expected payment. No contract is required, but the plaintiff must show the services were rendered under an understanding or expectation of both parties that compensation would be made. (Huskinson & Brown v. Wolf (2004) 32 Cal.4th 453, 458.)

Is unjust enrichment a cause of action in California?

California courts are split. Some treat unjust enrichment as a standalone claim; others treat it as a general principle supporting restitution through claims such as quantum meruit, money had and received, or constructive trust. The practical answer is to plead the specific restitution claim the facts support rather than rely on the unjust enrichment label alone.

How are quantum meruit damages calculated?

By the reasonable value of the services, measured by the going rate for that kind of work, provided the services benefited the defendant. The measure is not the profit the defendant later made from the work. (Maglica, supra, 66 Cal.App.4th at p. 449.) Time records, rate cards, and comparable invoices are the usual proof.

Can I sue for unjust enrichment if I have a contract?

Usually not for the same subject. Where a valid, enforceable contract covers the work and fixes the price, the plaintiff is confined to the contract. Quantum meruit applies when there is no enforceable agreement, when the agreement does not cover the work in question, or when the contract has been rescinded.

What is the statute of limitations for quantum meruit in California?

Generally two years, because the claim is an obligation not founded on a writing. (Code Civ. Proc., § 339, subd. 1.) The period usually runs from when the work was finished or payment was refused. If a written contract covers part of the relationship, the related contract claim may have four years, so the theories should be evaluated together.

Talk to a California breach of contract attorney

If your business provided value it was not paid for, or is facing an unjust enrichment claim, call (909) 235-6116 or contact us online. Kolmogorov Law, P.C. is located at 327 Magnet, Irvine, CA 92618, and represents businesses in Orange County, Los Angeles, and throughout California.

This page provides general information about California law and is not legal advice. Outcomes depend on the facts, the evidence of value, and the court.