AGI, or adjusted gross income, is your gross income minus any allowable adjustments or subtractions. For example, it's all the money you earned in a year, with the costs of your IRA contributions and student loan interest payments deducted. MAGI, or modified adjusted gross income, is a different method of calculating your AGI. To get your MAGI, you'll add back in some of the deductions and subtractions you took out previously.