Start with your total income for the tax year (e.g., wages, interest, dividends, capital gains, business income, retirement income).
Subtract any “above-the-line” deductions you qualify for, such as:
Educator expenses
Certain business expenses for self-employed individuals
Health savings account (HSA) deductions
Moving expenses (if eligible)
Deductible part of self-employment tax
Self-employed retirement plan contributions
Keogh/SEP/SIMPLE contributions
Penalty on early withdrawal of savings
Alimony paid (if applicable under the applicable divorce date rules)
IRA deductions
Student loan interest
Tuition and fees (if applicable for the tax year)
Certain other adjustments allowed for the tax year
Compute AGI:
AGI = Total income − Total above-the-line adjustments
Use the worksheet or calculations on Form 1040 (or the applicable form for your situation) to confirm the AGI figure.
If the question is about “MAGI,” start from AGI and apply additional required modifications specific to the tax benefit being calculated.