Modified adjusted gross income is adjusted gross income that is modified by certain amounts specific to the given limitations. Most limitations that affect adjusted gross income are the deductions and credits that are available to the tax payer. In the United States, adjusted gross income or AGI, is the calculation of an individual's tax liability after any and all types of deductions and credits have been factored in. The wages used for this type of adjustment include virtually all types of wages. There are various modified adjusted gross incomes available and each one is computed in a different way. These need reported to the IRS on tax returns filed yearly. The most common used is the Modified AGI for Roth IRA.