The threshold is lower than most people assume. The traditional test asks whether, at the time of signing, the person understood that they were making a will, had a general sense of what they owned, knew who their natural beneficiaries were, and could form a coherent plan for distributing the estate. It is not a test of sharpness, memory, or good judgment.
Crucially, capacity is measured at a moment rather than over a period. Someone with a dementia diagnosis may still have lucid intervals, and a will signed during one can be valid. Conversely, a person who seemed fine generally may have lacked capacity on a particular afternoon. This is why attorneys note the circumstances of a signing and why the timing of the appointment matters.
Contests on this ground are common and usually hard to win, because the presumption favors capacity and the challenger carries the burden. Medical records, testimony from the drafting attorney and the witnesses, and the coherence of the document itself all bear on it. A will that makes internal sense is evidence in its own favor.
Capacity for a will is also generally treated as a lower bar than the capacity required for other legal acts, such as signing a contract or a complex trust. The standards are set by state law and their application is fact-intensive, so a general description is a starting point rather than an answer about any specific person.
Frequently asked
- Can someone with dementia make a valid will?
- Possibly, yes. A diagnosis is not a legal determination of incapacity. What matters is the person's understanding at the moment of signing, and cognitive conditions often leave lucid periods in which the traditional test is satisfied. Practically, a signing under these circumstances should be documented carefully — an attorney's contemporaneous notes, a physician's assessment near the date, and reliable witnesses all matter far more than usual.
- How is this different from undue influence?
- One is about ability, the other about freedom. A capacity challenge argues the person did not understand what they were doing. An undue influence challenge concedes they understood perfectly and argues someone else overrode their will. They are often pleaded together because diminished capacity makes a person more susceptible to pressure, but they are distinct claims proved with different evidence.
- How do you prove capacity years after the fact?
- Through whatever record exists, which is why creating one matters. The drafting attorney's notes and testimony, the witnesses' recollections, medical records from around the signing date, and the document's own internal coherence all carry weight. Contemporaneous evidence is worth more than anything reconstructed later. Where a will is likely to surprise someone, building that record at the signing is the single most effective defense against a future challenge.