If you use your car for deductible moving or medical purposes, you can add the cost of driving based on a standard mileage rate. For 2008, the rate is 19
Gross income less allowable adjustments, such as IRA, alimony, and Keogh deductions. AGI determines whether various tax benefits are phased out, such as personal exemptions, itemized deductions, and the rental loss allowance and modified adjusted gross income (MAGI).