Testamentary Capacity. When does a person lack the ability to make a valid Will?

What is “testamentary capacity”?

The legal test for assessing testamentary capacity was outlined almost 150 years ago in a case called Banks v Goodfellow (1870) LR QB 549. The test has four (4) aspects to it, namely:

1. That the willmaker understands the nature of the act of making a Will and its effects,

2. That the willmaker understands the extent of the property of which he or she is disposing,

3. That the willmaker is able to comprehend and appreciate the claims to which he or she ought to give effect, and

4. That no insane delusion shall influence the Will of the willmaker in disposing of his or her property and bring about a disposal of it which, if the mind had been sound, would not have been made.

If any one of those four aspects of capacity is missing, then a valid Will cannot be made.

Whilst Banks v Goodfellow continues to be applied, it is now applied taking into account the differences between life in 1870 and life in modern times. That is particularly so of the requirement that a person “understand the extent of the property of which he is disposing“, which can be considerably more complex than it once was.

For example, a Will is still likely to be valid even though a person may not know how much income is derived from real estate investments, precisely what shares he or she owns in a managed share portfolio, or if he or she cannot recall a particular investment at the time that instructions are provided for the preparation of a Will.

The test does not require a person to have perfect mental balance and clarity, and a Will is still valid provided that he or she retains sufficient intelligence to understand and appreciate the testamentary acts in its different bearings.

Similarly, it is not necessary to establish that a person understood every clause in his or her Will. It will be sufficient if the person understood that he or she was executing a Will, and was aware of the practical effect of the central clauses in that document (including the dispositions of property made and the implications for the estate of the appointment of those who are to administer it).


The existence of a delusion of the mind will not automatically be sufficient to render a Will invalid. What is important is whether or not the delusion influenced the Willmaker’s making of the Will and had an effect upon its terms.

For example, a person may have formed an opinion that is harsh and unreasonable, but that does not mean that he or she necessarily lacks the capacity to make a valid Will. That is because, as it was put by the New South Wales Court of Appeal in Easter v Griffiths (Unreported, NSWCA, 7 June 1995):

Testamentary capacity is not reserved for people who are wise and fair, or reasonable, or whose values conform to generally accepted community standards. A person may disinherit a child for reasons that would shock the conscience of most ordinary members of the community, but that does not make the will invalid.”

The real question is whether the delusions impacted upon the judgment of the person to such an extent as to render him or her incapable, taking a rational view of the matters to be considered in making a Will, of making a reasonable proper disposition of his or her property.

It is also clear that a delusional state of mind does not need to be permanent for a Will to be considered invalid. In other words, a finding that a person did not have the capacity to execute a Will on a particular date would not necessarily exclude a conclusion that, either shortly before or shortly after the execution of that Will, the person may have had sufficient judgment and sanity to enable him or her to make a valid Will.

Knowledge and approval and suspicious circumstances

On occasion there will be a question raised about whether or not a willmaker knew what was written in his or her Will when he or she executed it. That concern may arise because of, for example, the circumstances in which the document was put before the testator for execution or because words were inserted (either intentionally or by mistake) without the testator’s knowledge and approval.

Generally speaking, where there are no suspicious circumstances which cast doubt over whether or not the provisions of a Will were fully known to and approved by a willmaker, proof of both capacity and the proper execution of the Will creates a presumption that he or she knew of and assented to its contents.

However, where suspicious circumstances do exist, the person propounding the Will has the burden of affirmatively proving, by clear and satisfactory evidence, that the willmaker knew and approved of the contents of the Will.

For example, if a person who takes a benefit under a Will actually wrote or prepared the document, and there is some challenge to the validity of the Will, it will generally result in a careful examination by the Court of the evidence as to the willmaker’s appreciation and approval of the contents of the Will.

Undue Influence

In Wills and Probate law there is no presumption that, simply because a certain type of relationship exists between the willmaker and a beneficiary, a particular benefit given in the Will has come about as a result of undue influence.

The influence of a person will only invalidate a Will if it is proven to be contrary to the free exercise of judgment by the willmaker, and the degree of coercion sufficient to constitute undue influence may vary with the circumstances so that, for example, very little may be required in the case of an old and feeble testator.

It follows that there is often nothing wrong with a person seeking to persuade or appeal to the affection of another person in order to seek in inclusion in that person’s Will.

The following statement, made in a case called Wingrove v Wingrove (1885) LR 11 PD 81, summarises the test:

To be undue influence in the eye of the law there must be to sum it up in a word coercion It is only when the will of the person who becomes a testator is coerced into doing that which he or she does not desire to do, that it is undue influence.

[Undue influence] may be in the grossest form, such as actual confinement or violence, or a person in the last days or hours of life may have become so weak and feeble that very little pressure will be sufficient to bring about the desired result, and it may even be, that the mere talking to him at that stage of illness and pressing something upon him may so fatigue the brain, that the sick person may be induced, for quietness’ sake, to do anything. This would equally be coercion, although not actual violence”.

The individual circumstances of the deceased therefore need to be considered because an act that may not constitute undue influence in the case of one person may constitute undue influence in the case of a more susceptible individual. The onus of proving undue influence is borne by the party alleging it and, because the willmaker cannot give evidence, the evidence relied upon will often be circumstantial.


While the Court does not exercise its power according to idiosyncratic or subjective views about what is thought to be “fair” or “wise“, or seek to unnecessarily restrict the testamentary freedom of a capable and competent person, there are situations in which Wills are declared invalid because the willmaker lacked the capacity to properly appreciate what he or she was doing, or was subject to an improper external influence.

If you have a concern about a Will, or are involved in a situation where someone has challenged the validity of a Will, call us for a free, no obligation phone evaluation.

By Matthew Bryan