what age is a child to be considered a dependent for tax purposes
1 The child must be under 19 at the end of the year and younger than you (or your spouse if filing jointly), under age 24 if a full-time student and is younger than you (or your spouse if filing jointly), or any age if permanently and totally disabled. A spouse can never be a dependent. 2  If you can be claimed as a dependent on someone elseâs tax return, you cannot claim anyone as a dependent. 3  If you had a child on December 31, you can claim them as an exemption for the entire year.