The income threshold varies depending on which educational credit / deduction you are planning on taking and your filing status. For each one, there is a point at which the phaseout begins and ends (i.e you can get a partial deduction when the phaseout begins but get no deduction when the phaseout ends). For income thresholds, the number of students is not factored into the calculation.
The modified adjusted gross income limit for married filing jointly is $130,000 - $160,000 for the tuition and fees deduction, $160,000 - $180,000 for the American Opportunity Credit, $112,000 - $132,000 for the lifetime learning credit, and $135,000 - $165,000 for the student loan interest deduction. When your income exceeds these levels, you are not allowed to claim the educational benefit.
The modified adjusted gross income limit for single, head of household, and qualifying widower is $65,000 - $80,000 for the tuition and fees deduction, $80,000 - $90,000 for the American Opportunity Credit, $56,000 - $66,000 for the lifetime learning credit, and $65,000 - $80,000 for the student loan interest deduction. When your income exceeds these levels, you are not allowed to claim the educational benefit.
Note: If you are married filing separately, then you are NOT allowed to take any of these educational benefits.
https://www.irs.gov/credits-deductions/individuals/tuition-and-fees-deduction-at-a-glance
https://www.irs.gov/credits-deductions/individuals/aotc
https://www.irs.gov/credits-deductions/individuals/llc
