What are the types of mistakes in contract law?

Asked by: Georgianna Glover  |  Last update: May 3, 2025
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Common law has identified three different types of mistake in contract: the 'unilateral mistake', the 'mutual mistake', and the 'common mistake'. The distinction between the 'common mistake' and the 'mutual mistake' is important.

What are common mistakes in contract law?

One of the types of mistake is a 'common mistake'. A common mistake is where both parties are mistaken about the same thing. The shared mistake must be about something that is a serious aspect of the contract – it cannot be about something not sufficiently serious.

What are mistakes in contracts allow it to be?

In terms of the wording and the contents of the contract itself, absent any involved parties' agreement, certain mistakes may make the contract void and unenforceable as a matter of law. Similarly, the contract may be valid unless one party wants to invalidate it.

What type of mistake will serve as a valid defense to a contract?

Mistakes can also be either unilateral or mutual. A unilateral mistake is when only one of the contracting parties makes a mistake. The contract is usually still valid and legally enforceable, unless the mistake is a palpable unilateral mistake.

What are the types of unilateral mistake in contract law?

In this case, one party misunderstood the conditions of a contract — and the other party was not aware of it. A unilateral mistake can be “palpable” or “impalpable” — two terms which we will define next with respect to their legal context — and this distinction dictates the type of remedy applied to a contract.

Unilateral and mutual mistakes

19 related questions found

What are the three types of mistakes?

The three types of mistake recognised by the law are:
  • common mistake.
  • mutual mistake, and.
  • unilateral mistake.

What are the classification of mistakes in a contract?

Common law has identified three different types of mistake in contract: the 'unilateral mistake', the 'mutual mistake', and the 'common mistake'. The distinction between the 'common mistake' and the 'mutual mistake' is important.

What are the two types of mistake defenses?

Put simply, in a mistake of fact defense, the defendant claims they didn't have the intent to commit the crime because they did not understand a particular fact. Likewise, in a mistake of law defense, a defendant will show they didn't have the mental state to commit a crime due to a misunderstanding of the law.

What is the difference between a mutual mistake and a unilateral mistake?

A unilateral mistake occurs when only one party is mistaken as to the subject matter or the terms contained in the contract agreement. This type of mistake is generally more common than other types of contract mistakes, such as a mutual mistake (an error that is shared by both parties).

Can a typo invalidate a contract?

If you enter into a contract, you and the other party are bound to the terms of that contract. If you and the party both sign a contract with typos, then you are both bound to the terms of the contract, typos and all.

What are the five mistakes that may invalidate a contract?

What are the Most Common Mistakes that may Invalidate a Contract?
  • The Incapacity to Enter into a Contract. ...
  • No Consideration. ...
  • Vague or Ambiguous Terms. ...
  • Signing Under Duress or Coercion. ...
  • Fraud or Misrepresentation. ...
  • Failure to Meet Formal Requirements. ...
  • Illegal or Unenforceable Terms.

What is the most significant violation of a contract?

Sometimes referred to as a total breach, a material breach is considered the most serious because one party failed to perform the duties detailed in the contract. Thus, the breach is so significant, the purpose of the agreement is determined to be completely broken.

What types of mistakes will allow rescission of a contract?

The court must find a valid legal basis for rescinding the contract, such as misrepresentation, mistake, duress, undue influence, incapacity, or illegality. Rescission by court order is subject to judicial discretion and equitable principles.

What constitutes a mistake for purposes of contract law?

In contract law , a mistake usually refers to a situation where the parties did not mean the same thing when they agreed to a term or provision.

What are the three types of misrepresentation?

There are three types of misrepresentations—innocent misrepresentation, negligent misrepresentation, and fraudulent misrepresentation—all of which have varying remedies.

What is the last shot rule in contract law?

In this situation, the battle is often won by the party who fired the "last shot", that is, the last party to put forward terms and conditions that were not explicitly rejected by the recipient.

Can a contract be voided because of a mistake?

If both contracting parties make a mistake regarding facts considered to be material, the party that is negatively affected may get out of the contract. This will typically arise when there is a lack of existence of the subject matter. Mutual mistake can either result in a void or voidable contract.

What is a Scrivener error?

Scrivener's error is a mistake made by someone who is writing or copying something down, like a typo or a misspelling. It is a type of clerical error, which means it is not a mistake made by a judge or based on legal reasoning. Scrivener's errors can be corrected at any time, even after a judgment has been made.

What is a common mistake in contract law?

Common mistake (where the mistake is shared by both parties, is fundamental and directly affects the basic definition of what the parties are contracting for). The mistake will render the contract void if it robs it of all substance. Mutual mistake (where the parties are at cross-purposes with one another).

How to prove mutual mistake?

To invoke the doctrine of mutual mistake, a party must present proof that the agreement, as expressed, does not represent a “meeting of the minds” between the parties in some material respect. The mutual mistake must be substantial3 and exist at the time the parties enter the contract.

What is the difference between a mistake and a misunderstanding in contract law?

A mistake is a belief not in accord with the facts. Where there is a misunderstanding, though, the belief of each party is in accord with the facts, just not with each other. As such, a true misunderstanding is not a mistake at all.

What is legal duress?

CALIFORNIA LEGAL DEFENSES: DURESS

Duress is a rarely-used defense that applies in situations in which someone commits a crime only because of an immediate threat to life posed by another. The typical example is committing a criminal act only because there is literally “a gun to your head.”

What is the difference between a mutual and unilateral mistake?

The two forms of mistakes of fact are mutual mistakes and unilateral mistakes. A mutual mistake occurs when both parties have an erroneous belief while a unilateral mistake only involves the misunderstanding of one party.

Does a unilateral mistake void a contract?

A party to a contract is entitled to reformation of the contract based on one party's unilateral mistake only if the other party engaged in inequitable conduct. A party acts inequitably if it knowingly conceals a material fact from the other party and has a duty to disclose that knowledge to the other party.

Is a contract void if the date is wrong?

So long as it is clear what the correct date was and the error doesn't make the contract ambiguous, it is binding. For example, if a contract signed today (7/3/2023) said I would watch your dog for seven days, starting 7/4/2023 and ending 7/10/2022, it is clear to everyone the second date should have been 2023.