What this line means
Your total income (line 9) minus adjustments from Schedule 1, Part II. Adjustments include deductible IRA contributions, student loan interest, health savings account deductions, and the deductible half of self-employment tax. AGI is the single most important number on your return — it determines eligibility for dozens of credits, deductions, and income-based thresholds.
Does this apply to you?
- You filed a tax return with any amount of income
- You are calculating whether your income triggers Medicare premium surcharges (IRMAA)
- You need to determine the taxable percentage of your Social Security benefits
- You are checking eligibility for the Credit for the Elderly or Disabled
- You are applying for income-based programs that use AGI as the qualifying measure
Easy to overlook
AGI controls Medicare Part B and D premium surcharges Medicare uses your AGI from two years prior to set income-related monthly adjustment amounts (IRMAA). For 2025, if your 2023 AGI exceeded $103,000 (single) or $206,000 (married filing jointly), you pay higher Medicare premiums. A one-time event like a Roth conversion or property sale can push AGI above the threshold and trigger surcharges for two years. 1 IRS Form 1040-SR Instructions — Line 11
The Credit for the Elderly or Disabled has a strict AGI ceiling If you are 65 or older and your AGI exceeds $17,500 (single) or $20,000 (married filing jointly), you cannot claim the Credit for the Elderly or Disabled on Schedule R. This credit phases out quickly, and many seniors with moderate pension and Social Security income exceed the limit without realizing it. 2 General filing pattern — AGI threshold impact on senior benefits
Watch out for this
Confusing AGI (line 11) with taxable income (line 15). AGI is before the standard deduction. Taxable income is after. Programs that reference “adjusted gross income” — including IRMAA, Medicaid eligibility, and ACA premium subsidies — use line 11, not line 15. Reporting the wrong number on applications causes eligibility errors.
Footnotes
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IRS Form 1040-SR Instructions, Line 11, Adjusted Gross Income. https://www.irs.gov/instructions/i1040sr ↩
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IRS Schedule R Instructions, Credit for the Elderly or the Disabled. https://www.irs.gov/instructions/i1040sr ↩