He should be classified as a dependent since he lives at home and I cover all bills. If he needs to file his own taxes, do I still claim his as a dependent?
Maybe. The dependency test has 7 requirements that vary depending on child or qualifying relative. You can take this quick online quiz, Whom May I Claim as a Dependent?
Here is a Worksheet for Determining Support. See 2020 Publication 501 - Internal Revenue Service page 10 to verify that you qualify to claim the dependent.
He will probably need to file a return. Quick quiz, Do I Need to File a Tax Return?
Q. Do I still claim his as a dependent?
A. Simple answer: yes. Being in high school counts as being a full time student.
There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test.
A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:
So, it doesn't matter how much he earned. What matters is how much he spent on support. Money he put into savings does not count as support he spent on him self.
The support value of the home, provided by the parent, is the fair market rental value of the home plus utilities & other expenses divided by the number of occupants.
The IRS has a worksheet that can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf
Furthermore, there is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim himself. If he has sufficient income (usually more than $12,400), he can & should still file taxes. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section. TT will check that box on form 1040.