Financial Glossary
Adjusted Gross Income (AGI)
Adjusted Gross Income (AGI) is a foundational tax concept representing total gross income from all sources -- wages, self-employment income, rental income, interest, dividends, capital gains -- reduced by a specific set of above-the-line deductions permitted without itemizing. Common above-the-line adjustments include contributions to traditional IRAs and self-employed retirement plans, the self-employment tax deduction, health insurance premiums for self-employed individuals, student loan interest, and alimony under agreements governed by pre-2019 law. AGI functions as the gateway figure for many downstream tax calculations: numerous credits and itemized deductions phase out or are limited based on AGI levels.
Problem & Application
A self-employed campground consultant earns $180,000 in net self-employment income. Contributing $46,000 to a solo 401(k) and deducting 50 percent of self-employment tax ($12,700) and health insurance premiums ($14,400) brings AGI down to approximately $107,000. The lower AGI may restore eligibility for deductions that would have phased out at the higher figure and reduces the adjusted income used to calculate the net investment income tax exposure on any passive income. For business owners with multiple income streams -- self-employment, rental properties, pass-through S corporation income -- optimizing AGI through retirement contributions and entity structuring is one of the highest-value tax planning levers, and it must be revisited annually as income levels shift.
In Short
Adjusted Gross Income is a cornerstone of tax calculations, determining eligibility for credits and deductions. Accurate calculation and understanding of AGI help individuals and businesses minimize tax burdens and comply with regulations.