Mental Capacity Requirements in Estate Planning

two old men playing chess in a park

A primary requirement when signing a legal document, including a Last Will and Testament or other estate planning tool, is that the person signing must have sufficient mental capacity or competency to understand the document he or she is signing. It is essential to understand the nuances of the capacity requirement because lack of capacity is one of the most common ways a Will can be contested.

Levels of Capacity

An often-unknown fact is that courts often require different levels of capacity for certain legal documents. For example, depending upon the state, a court may have a heightened capacity requirement for the signing of a lease or similar contract. With a contract, there needs to be a “meeting of the minds,” and one’s mental capacity is critical. Unlike a contract, many states have a lower capacity requirement for signing estate planning documents, like a Will.

While each state’s definition of capacity is different, the key requirements are basically the same. In general, the capacity standard requires that the testator, or person signing the Will, understand, in a general way, the nature and extent of the property and assets and relationships with family and friends.

It also requires the testator to be free from delusion which may be caused by disease or injury that might influence decisions concerning assets. Finally, courts require the testator to comprehend the nature of the act of creating a Will. Basically, the testator needs to understand that he or she is signing their own Will and be cognizant of how and to whom he or she is distributing assets.

The capacity requirement for signing a Will in most states is limited to the day the Will is signed. For example, if the testator has capacity and signs his or her Will, then the next day suffers a head injury and cannot remember signing it, the Will is still considered to be valid.


The capacity rule is especially important for someone who has dementia. Just because a person has been diagnosed with Alzheimer’s or dementia may not mean that it is too late for them to sign a Will. The critical element in determining if the Will is valid is the capacity of the person at the time the Will was signed. If the person was experiencing a period of lucidity, was thinking clearly, and understood that he or she was signing his or her Will, it can be valid. It is important to note that having witnesses and a notary public witness the signing of the Will may help defeat any challenge as to capacity in the future. In the event of a challenge, the witnesses and notary will be asked to testify that the person signing had the requisite clarity and capacity.

Challenging a Will

One of the most common ways a Will is challenged is on capacity grounds. In some instances, beneficiaries who are unsatisfied with their share of the descendant’s estate use capacity as a way to try to invalidate the Will. For example, if a testator suffering from dementia signs a Will which deliberately excludes a sibling, that sibling (who is likely angry) could hire a lawyer and argue that the Will is invalid. As part of the defense of the Will, the executor would have to call on witnesses who would testify that the testator had the necessary capacity at the time he or she signed, despite the dementia.


A Will should never be signed alone or with only one person present. Wills should always be signed in front of at least two witnesses and a notary public even if your state doesn’t require a Will to be notarized. If the Will is witnessed and notarized, the estate has a much better chance of defending a Will contest.

Video the Signing

Another tactic people use to protect the estate and testator from a Will contest is video. In addition to witnesses and a notary, it could be useful to video record the person during the signing of the Will. Video can be admissible in court and can give the judge a much better picture of the mental capacity of the testator at the time the Will was signed.

Testator’s Competency

The mental capacity of the testator is a crucial requirement of a valid Will. Thus, it is essential to take all necessary steps to document that the testator was competent at the time of signing. This is best accomplished through witnesses, a notary public, and even through video which could be uploaded and stored in your Gentreo Digital Vault.

For more information, visit us at We provide a simple and affordable way to create a heath and estate family plan.

Gentreo is not a law firm or a substitute for a law firm, or attorney, or an attorney’s advice or recommendations.


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