Adjusted Gross Income, or AGI, is the all-important line item on your tax return. According to the IRS, AGI represents your total income minus certain adjustments given by Uncle Sam. But we don't have to get too technical at this point; basically what you need to know is you can find your AGI on your most recent tax return.  plays a huge role in the calculation of your monthly payment for federal student loans if you are in an income-driven repayment plan (PAYE, REPAYE, IBR, ICR). AGI isn't the only factor in the calculation of your monthly payment, but it certainly is a big one.