- Capacity is assessed relative to a specific decision, at a specific point in time — not as a permanent, global label attached to a person.
- Courts assessing testamentary capacity generally look at whether, at the time the will was made, the person could: - Understand, in general terms, what a will is and what making one does…
It's a common assumption that a person either "has capacity" or doesn't, as though it were a single switch. Ontario law doesn't work that way. The types of legal capacity Ontario recognizes are decision-specific: the test for whether someone can validly make a will is different from the test for managing their own finances, which is different again from the test for personal care decisions.
This distinction matters more than it might seem. A dementia diagnosis, for example, doesn't automatically strip away every kind of legal capacity at once — someone can be unable to manage their day-to-day finances while still being capable of making a valid will, or the reverse.
This article walks through the main types of capacity that come up in estate planning, what courts generally look at, and why a diagnosis alone rarely settles the question.
Why "Capacity" Isn't One Thing
Capacity is assessed relative to a specific decision, at a specific point in time — not as a permanent, global label attached to a person. A person's ability to make one kind of decision doesn't automatically say anything about their ability to make a different kind.
A Look at the Main Types of Capacity in Estate Planning
| Type of capacity | What it's about | Where it comes up |
|---|---|---|
| Testamentary capacity | Understanding what a will does and being able to make one validly | Making or changing a will |
| Capacity to grant a Power of Attorney for Property | Understanding what you're authorizing someone else to do with your finances | Signing a Continuing Power of Attorney for Property |
| Capacity to grant a Power of Attorney for Personal Care | Understanding what you're authorizing someone else to decide about your health and personal care | Signing a Power of Attorney for Personal Care |
| Capacity to manage property | Whether a person can currently manage their own financial affairs | Relevant if guardianship of property is being considered |
| Capacity for personal care | Whether a person can currently make decisions about their own health, safety, or living arrangements | Relevant if guardianship of the person is being considered |
What Courts Generally Look At for Testamentary Capacity
Courts assessing testamentary capacity generally look at whether, at the time the will was made, the person could:
- Understand, in general terms, what a will is and what making one does
- Understand, in general terms, the extent of the property being dealt with
- Be aware of the people who might reasonably expect to benefit, and evaluate their claims, even if the final decision doesn't favour them
A Diagnosis Is Evidence, Not an Automatic Answer
A diagnosis such as dementia doesn't, on its own, mean someone lacks the capacity to make a valid will. Capacity is a legal conclusion assessed at the time a specific document was signed, and a medical diagnosis is one piece of evidence relevant to that assessment, not a complete answer by itself.
The same basic idea tends to come up whenever any of the capacities described above is questioned: a diagnosis alone rarely resolves the legal question on its own, though exactly how capacity is assessed can differ by document type. This is precisely why acting promptly after a diagnosis, rather than assuming it's already too late, matters.
Why This Matters for Families
Someone might be capable of appointing a Power of Attorney for Property but no longer able to manage their day-to-day finances without help. These aren't contradictory findings — they're different legal questions with different tests, which is part of why starting planning conversations early gives a family more options, not fewer.
Frequently asked questions
If someone has dementia, does that mean they can't sign a new will or power of attorney?
Not automatically. A diagnosis is relevant evidence, but the legal question is whether the person had the specific understanding required for that particular document at the time they signed it. This is exactly why acting promptly after a diagnosis, rather than waiting, matters.
Who decides whether someone has capacity?
It depends on the context. A lawyer forms their own assessment before helping someone sign a legal document, and in some situations a more formal capacity assessment is appropriate. Health care providers, and in disputed cases courts, can also be involved.
Can someone be capable of making a will but not capable of managing their own money?
Yes. These involve different legal tests aimed at different questions, so it's entirely possible for one to be met and not the other.
What should I do if I'm worried about a family member's capacity?
Speak with a lawyer promptly. Waiting can narrow your options, particularly if you're hoping to help them put updated planning documents in place while they're still able to do so.
This is a wills & estates question
Start a file online — flat, published fees, reviewed by a licensed Ontario lawyer before a dollar is owed.