The legal ability of a person to understand information relevant to a decision and to appreciate the consequences of making or not making that decision. Required capacity varies by decision type and can fluctuate over time.
Your ability to understand what you're doing and make decisions for yourself. It's not about whether you make wise decisions others agree with—it's about whether you understand what you're deciding and the consequences.
⏱ When you'll encounter this term
- Making a will (testamentary capacity required)
- Signing legal documents like powers of attorney
- Questions about dementia or cognitive decline
- Challenges to wills or legal documents
- Guardianship or conservatorship proceedings
"The doctor assessed Dad's mental capacity before he signed his will. She confirmed he understood his assets, his family situation, and what the will meant."
💡 Did you know?
Mental capacity is decision-specific—you might have capacity to make some decisions but not others. Someone with dementia might still have capacity to make a will on a good day, even if they struggle with daily tasks.