Gross Income vs AGI: Where Line 11 on Your 1040 Comes From
Gross income and AGI (Adjusted Gross Income) are often confused. They appear at different points on your 1040, they differ by the amount of your above-the-line adjustments, and almost every tax benefit phase-out uses one or the other - but not always the same one.
The Form 1040 Cascade
Gross Income
All income from all sources: W-2, 1099, K-1, interest, dividends, cap gains, rental, retirement
minus: Above-the-Line Adjustments
IRA, HSA, student loan interest, half SE tax, educator expenses - see full list below
Adjusted Gross Income (AGI)
The key number used by most phase-out calculations
minus: Standard or Itemised Deduction
~$15,000 single / $30,000 MFJ for 2026; itemise only if exceeds standard
minus: QBI Deduction (if applicable)
Section 199A: up to 20% of qualified business income for pass-through owners
Taxable Income
The number brackets are applied to
Total Tax
Your actual federal income tax liability for the year
Above-the-Line Adjustments: The Full 2026 List
| Adjustment | 2026 Limit | Notes |
|---|---|---|
| Educator expenses | $300 | K-12 classroom teachers; $600 MFJ each educator |
| HSA deduction | $4,300 single / $8,550 family | For self-only HSA contributions not via Sec 125 payroll |
| Self-employed retirement (SEP, SIMPLE, Solo 401k) | Up to 25% / $69,000 | Solo 401k: employee + employer up to $69,000 |
| Half of self-employment tax | Calculated on Schedule SE | Reduces AGI by exactly half of SE tax paid |
| Self-employed health insurance | Premiums paid | Cannot exceed net SE income; not available if employer plan available |
| Traditional IRA deduction | $7,000 / $8,000 age 50+ | Phase-out if covered by employer plan: $77k-$87k single (2026 est.) |
| Student loan interest | $2,500 max | Phase-out: $75k-$90k single (2026 est.) |
| Penalty on early CD withdrawal | Amount forfeited | When bank charges early withdrawal penalty on savings certificate |
| Alimony paid | Amounts per decree | Only for divorce agreements executed before Jan 1, 2019 |
| Moving expenses (military only) | Actual costs | Post-TCJA 2017, available only for active-duty military |
Source: IRS Publication 17 (2026). Limits are inflation-adjusted annually. Verify via IRS.gov before filing.
Why AGI Matters: Every Phase-Out That Uses It
Roth IRA Contribution Eligibility
Phase-out $150k-$165k single (2026 est.)
Uses MAGI, not plain AGI
Child Tax Credit
Phase-out above $200k single / $400k MFJ
Uses MAGI
Student Loan Interest Deduction
Phase-out $75k-$90k single
Uses MAGI
Medical Expense Itemised Deduction
Floor = 7.5% of AGI
Uses AGI directly
Charitable Deduction (cash gifts)
Limited to 60% of AGI generally
Uses AGI
IRMAA (Medicare premium surcharge)
Starts at $106,000 MAGI single (2026 est.)
Based on 2-year-prior MAGI