A child who provides over one half of his or her own support generally is not considered a qualifying child of another taxpayer. However, a child who provides over one half of his or her own support may constitute a qualifying child of another taxpayer for purposes of the earned income tax credit.

The term “support” and “income” have entirely different meanings. The question is, does a child provide over half of his or her own support? A child may have income, save it, and not contribute to their own support, in which case the child may very well be the qualifying child of his or her parents, who would be entitled to claim the child as a dependent and claim a higher education tax credit for the tuition they paid. It may present an odd looking dependent of another return, but it is what it is. Also remember there is no gross income test for a “qualified child.”

For a “qualifying child,” the support requirement will be that the dependent had not provided over one-half of his or her own support for the calendar year in which the taxpayer's tax year begins. In determining whether a child provided more than one-half of his or her own support (for a qualifying child), or whether a taxpayer provided more than one-half of a relative's support (for a qualifying relative), the amount of support provided by the child, or by the taxpayer, will be compared to the total amount of support from all sources. The term “support” will include amounts incurred for support and/or the fair market value (FMV) of an item of support if the item is property or lodging. The amount of total support will include support provided for the dependent's own support, and income that's excludable from gross income. Support will include amounts spent (and FMV of goods or property used) to provide food and clothing, lodging (shelter), medical and dental care, education (but not certain scholarships), and similar items. Worksheet 2 in IRS Pub 501 is useful for determining support.

From Pub 929 (2021) – Page 24 – “Support - All amounts spent to provide the child with food, lodging, clothing, education, medical and dental care, recreation, transportation, and similar necessities. To figure your child's support, count support provided by you, your child, and others. However, a scholarship received by your child isn’t considered support if your child is a full-time student.”