The sum of all sources of taxable income, minus specific deductions, such as unreimbursed business expenses, medical expenses, alimony and retirement plan payments, and not including standard and itemized deductions. You state your AGI on Page 1 of your 1040 form, and it is used as a basis to establish eligibility for financial benefits such as IRA contributions, itemized deduction limits and social security benefits. Also referred to as "net income."