should both the full-time student and credit for other dependents box be checked?

[brown-mary]

For 2025 1040, 17 and 20 year old full-time students.

[Hal_Al · Accepted solution]

Yes on the 20 y.o. and no on the 17 y.o. This is because a child under 19, can still be a dependent even if not a FT student. 

There are two types of dependents, "Qualifying Children"(QC) and Other ("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:

1. He is under age 19, or under 24 if a full time student for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are excluded from the support calculation
3. He lived with the parent (including temporary absences such as away at school) for more than half the year