Legal Definitions - inessential mistake

An inessential mistake is a type of mistake in a contract that does not affect the validity of the agreement. It is a mistake that relates to some external circumstance and not the nature of the contents of the agreement. For example, if two parties agree to sell a car, but one party mistakenly believes the car is red when it is actually blue, this is an inessential mistake because it does not affect the validity of the agreement.

On the other hand, an essential mistake is a mistake serious enough that no real consent could have existed, so that there was no real agreement. For example, if two parties agree to sell a car, but one party mistakenly believes they are selling a boat, this is an essential mistake because it affects the validity of the agreement.

It is important to distinguish between essential and inessential mistakes because only essential mistakes can make a contract voidable. Inessential mistakes do not affect the validity of the agreement and therefore cannot be used as a basis for voiding the contract.