The requirements for Testamentary Capacity vary internationally but every country requires a testator (the Will maker) to have mental capacity at the time of making their Will.

Testamentary capacity means that the person making the Will should understand what a Will is and what its effect will be, know what their assets are and be aware of the persons for whom they would usually be expected to provide for, such as a spouse, or children.

If, following someone’s death, it is established that the person did not have capacity, then the Will would not be valid. In general, these are the requirements:

• Be in writing
• Is made by a person over 18 years of age (unless exemptions apply)
• Meets the formalities of signing and witnessing
• Is made voluntarily with understanding of the document and free from outside influence or fraud
• That the person making the Will (“the testator”) has the required capacity to do so (often referred to as being of sound mind)
• The testator should understand their act in making the Will and the effect of the Will
• They should understand what property they have and which is being dealt with/disposed of under the Will
• They need to appreciate the claims that may relate to their estate and who they Will be giving gifts/inheritances to
• They should not be suffering from a disorder of the mind that would impact their ability to make decisions or understand the Will and its impacts.

The test applies to the capacity of the testator at the time they are making the Will. This can be temporary (under the influence of medication, stress or illness) or permanent such as dementia.

If a Will appears rational, it is presumed that the testator had capacity to make it. It is up to the person disputing the Will to prove the testator did not have capacity.