Testamentary Capacity: What Mental Ability Is Needed In Order to Sign a Will?

Testamentary capacity refers to the mental ability required to make a Will. Generally speaking, people possess testamentary capacity if, at the time that the Will is executed, they: (1) are of adult age (in most jurisdictions that means over 18 years old), (2) understand the nature and consequences of executing a Will, (3) know the nature and extent of their property, and (4) recognize the people who are their family and loved ones. (Many jurisdictions also require the ability to apply this knowledge to create a coherent plan to dispose of their property at death.)

The nature and consequences of executing a Will
The person must understand that what he or she is doing is signing a Will and a basic understanding of how a Will works. This is because we want to make sure that it is the person’s intention to create a Will (not a contract, IOU, present gift, etc.). The person must understand that a Will transfers property at death and is binding once executed with the relevant legal formalities.

The nature and extent of the property
A person of sound mind is presumed to know the property he or she owns. So, for example, if a person makes a bequest of property that the person has never owned or does not currently own, this is an indication that the person does not have testamentary capacity.

Family and loved ones
The person must know the so-called natural objects of his bounty — the people who would be the expected recipients of the person’s assets. When a person cannot identify his nearest family and other loved ones, or tries, for example, to leave property to fictional characters or famous deceased people, this is an indication that the person does not have testamentary capacity. (Note: Pets may be loved ones to us, but for Will purposes they are legally considered property. Therefore, the best way to leave a bequest for the benefit of a pet is to set up a testamentary trust that funds and details the care and arrangements you want for your pet.)

Other mental issues
What about if a person has been diagnosed with dementia, or adjudicated incompetent, or has mental illness, or has a drug or alcohol addiction? Can that person still make a Will? Yes, so long as the components of testamentary capacity are met and/or the person did his Will during what is known as a lucid interval — i.e., a period of time during which the person was coherent and the threshold for testamentary capacity is met. Similarly, an insane delusion – a belief contrary to all rational objective evidence – does not prevent a person from making a Will; the delusion only invalidates any effected parts of the Will.

Testamentary capacity has the lowest threshold
Testamentary capacity is often described as being the lowest level of capacity needed in law — this is for public policy reasons: we want to encourage people to have Wills. Therefore, a person may not have enough mental capacity to, for example, enter into a contract, but can still do a Will as long as the elements of testamentary capacity are met.