Sometimes an adult son or daughter will move in with their parents. Parents will naturally wonder if their son or daughter will qualify as a dependent for tax purposes.
The thing to remember is that there are two categories of dependents under the tax code: qualifying children and qualifying relatives. Which category applies -- and thus whether the adult son or daughter qualifies as a dependent -- will depend on an analysis of these two sets of rules.
In general, if the son or daughter is at least 24 years old, they will likely fall under the category of qualifying relatives. Using that set of rules, the son or daughter will qualify as a dependent for the parents if the son or daughter earns less than their personal exemption amount (currently $3,650). This is called the gross income test. And gross income means all income before any deductions, and includes items such as wages, unemployment or freelancing. In many cases an adult son or daughter living at home will not qualify just based on this income test.
The income test does not apply, however, if the adult son or daughter meets the criteria to be a qualifying child. This includes kids under age 24 who are full-time students. The qualifying child rules also applies to sons and daughters of any age who are permanently disabled.