For a child under the age of 19 on Dec 31 of the tax year, their earnings do not matter. What does matter is support. If the child (not you) did not pay more than 50% of their own support, they qualify as your dependent.
For a child under the age of 24 on Dec 31 of the tax year *AND* a full time student for any one semester that started during that tax year, that same rule applies and again, their earnings do not matter.
If the child was 19-23 on Dec 31 of the tax year and was "not" a full time student for any one semester that started during the tax year, then the earnings requirement comes into play. If they earned more than $4,300 during the tax year, they do not qualify as your dependent.
