For every exemption you claim, you get a $3,050 deduction. Exemptions include children, parents, and other dependents. You can also claim an exemption for yourself, provided you are not counted as a dependent on someone else’s tax return. To qualify as an exemption, the dependent must be a relative of some type (though the relative does not have to live with you), and you contribute to more than half of the dependent’s support.
For a child to count as a dependent, the child must be under 19 years old, or 24 if a full-time student.