Legal Definitions - unessential mistake

An unessential mistake refers to an error or misunderstanding concerning a minor or non-fundamental aspect of a contract or legal agreement. Unlike an "essential mistake," which goes to the very core of an agreement and can sometimes allow a contract to be canceled, an unessential mistake does not affect the primary purpose, main terms, or fundamental nature of the agreement. Therefore, it typically does not provide grounds for a party to avoid their obligations or invalidate the contract.

Here are some examples to illustrate this concept:

• Example 1: Minor Product Description Error

  Imagine a company orders 500 units of "Model X" industrial valves from a supplier. The purchase order mistakenly lists the color of the valves as "dark gray" when the standard color, and the one the buyer expected and received, is "charcoal gray." The functionality, specifications, and price of the valves are all correct and as agreed.

  This is an unessential mistake because the error in color description does not change the fundamental product being purchased or its intended use. The buyer received the correct valves with the correct specifications, and the slight discrepancy in the written color description does not affect the core of the agreement.

• Example 2: Clerical Error in Property Address

  A contract for the sale of a commercial building correctly identifies the property by its legal description (lot and block numbers) and includes an accurate map. However, the street address is mistakenly written as "123 Main Street" instead of the correct "125 Main Street." Both the buyer and seller clearly understood which specific property was being bought and sold, having toured it multiple times.

  The incorrect street address is an unessential mistake. The legal description and the parties' clear understanding of the specific property being transacted ensure that the core subject of the contract is unambiguous. The minor clerical error in the street number does not alter the fundamental agreement to buy and sell that particular building.

• Example 3: Non-Critical Scheduling Detail

  A client hires a marketing agency to launch a new advertising campaign. The written contract specifies that the first draft of ad copy will be delivered on "Monday, May 15th." However, during a follow-up call, the parties verbally agree to a slightly earlier delivery date of "Friday, May 12th," which the agency meets. The client suffers no harm or delay due to the discrepancy between the written contract and the actual delivery date.

  The initial written date of May 15th, when the actual delivery was May 12th as mutually understood and executed, represents an unessential mistake. The core service (delivery of ad copy) was performed, and the minor difference in the written schedule did not fundamentally alter the project's outcome, the agency's obligations, or the client's expectations.