What is a contract formed by conduct without a signature?
When the parties proceed as if a contract exists despite not signing a formal writing, that is often described as a contract formed by conduct or an implied-in-fact contract.[1][2][3]
In the UCC context, if this is a sale of goods, the doctrine is more specifically captured by conduct recognizing the existence of a contract under UCC § 2-204 and, where the writings do not match, conduct by both parties which recognizes the existence of a contract under UCC § 2-207(3).[5][6]
Short answer
- General common law: implied-in-fact contract or contract implied by conduct.[1]
- UCC sale of goods: contract formed by conduct recognizing a contract under UCC § 2-204 and UCC § 2-207(3).[5][6]
- If one party relied on the other’s promise and acted to its detriment, the theory may instead be promissory estoppel.[1][4]
Practical distinction
| Situation | Likely label |
|---|---|
| Parties never signed, but both performed as though bound | Implied-in-fact contract / contract by conduct |
| Goods transaction with exchanged forms but no signed agreement | UCC contract by conduct; possibly UCC § 2-207(3) |
| One party relied on a promise without a contract | Promissory estoppel |
Under the common law, a contract can be formed by words or conduct, and contract law focuses on assent and consideration.[1] Under the UCC, a contract for the sale of goods “may be made in any manner sufficient to show agreement, including conduct by both parties which recognizes the existence of such a contract.”UCC § 2-204 [6]