Unilateral Contract
A contract where one party makes a promise that the other party accepts by performing an act, not by making a return promise.
While straightforward in theory, many businesses fail to actively track obligations tied to this concept - often resulting in missed deadlines, unintended renewals, penalties, or loss of contractual rights.
US Law · For business owners and foundersWhat is a Unilateral Contract?
A unilateral contract is an agreement where only one party makes a binding promise. The other party does not promise to do anything - instead, they accept the contract by actually performing the requested act. The promisor is only obligated to pay or perform once the act is completed.
The classic example is a reward: "I will pay $500 to whoever returns my lost dog." The person posting the notice makes a promise; everyone else is free to act or not. Once someone returns the dog, the contract is formed and the payment is due. There is no obligation to try, only an obligation to pay if the act is performed.
Unilateral contracts appear frequently in business as sales incentives ("earn a $1,000 bonus if you close 10 deals this quarter"), option agreements, insurance policies (pay premiums and coverage attaches), and certain real estate situations. Understanding the distinction from bilateral contracts helps in structuring obligations correctly.
In practice, many teams rely on a contract expiry tracking system to stay on top of dates and obligations tied to clauses like this.
Key Elements
One-sided promise
Only the offeror makes a promise. The offeree has no obligation to act - they can walk away at any point before completing performance.Acceptance by performance
The contract is formed when the offeree completes the requested act. A promise to perform is not enough - actual completion is required.Revocability before completion
The offeror generally can revoke a unilateral offer before performance is complete. However, once the offeree has substantially begun performance, many courts hold the offer irrevocable.Clear terms of the offer
The promise must be specific enough that the offeree knows exactly what act completes the contract. Vague reward offers create enforcement problems.Real-World Example
A software company sends a note to its sales team: "Anyone who brings in a new enterprise client worth over $100,000 ARR before December 31 will receive a $5,000 bonus." A rep closes a qualifying deal on December 28.
This is a unilateral contract. The company made a one-sided promise; the rep accepted by performing the act (closing the qualifying deal). The bonus is now owed. The rep had no obligation to try, but having completed the act, the company must pay.
This is why many businesses adopt automated deadline tracking to ensure no critical dates are missed before they pass.
Sample Clause Language
Unilateral incentive offer (sales bonus)Watch Out For
Revocation after partial performance
If someone has substantially begun performing in reliance on your offer, revoking it may expose you to a promissory estoppel claim. Consider stating explicitly when and how the offer can be revoked.Unclear completion criteria
If the terms of the act are ambiguous, the offeree may claim they completed it while you disagree. Define success criteria precisely.Confusing unilateral and bilateral
If you intend to form a binding agreement upfront (each side promises something), use bilateral contract language with mutual covenants rather than a unilateral offer structure.Don't let unilateral contract deadlines catch you off guard
Key dates tied to unilateral contracts - renewal windows, expiry cutoffs, notice periods - can easily slip through the cracks when tracked manually. Missing them triggers automatic extensions, penalties, or lost rights. ExpiryEdge tracks every critical deadline and sends automated reminders before they're due - so nothing slips.
Instead of relying on spreadsheets or manual follow-ups, a centralized renewal reminder system ensures every deadline is visible, tracked, and actioned automatically.
How to Use This in Your Favor
Define the qualifying act precisely
Specify exactly what counts as completion - date, dollar threshold, deal type, approval process. Ambiguous success criteria lead to disputes.State the revocation window
Include language specifying that the offer can be revoked at any time before a qualifying act is completed, with reasonable advance notice to participants.Use bilateral structure for ongoing obligations
If you need the other party to commit to trying (e.g., a sales rep who must make efforts), a bilateral contract with performance obligations is more appropriate than a unilateral offer.Frequently Asked Questions
Can a unilateral contract be breached before performance starts?
Generally no. Because the offeree has not promised anything, there is nothing to breach before they begin performing. The offeror can revoke the offer, but that is not a breach.
What if I start performing and the offeror revokes?
Once you have substantially begun performance in reliance on the offer, many courts will hold the offer open long enough for you to complete it. Document the date you began and your progress.
Is an insurance policy a unilateral contract?
Generally yes. The insurer promises to pay upon a covered loss; the policyholder has no obligation beyond paying premiums. Paying the premium is the act that keeps coverage in force.