How does MAGI differ from AGI on your federal tax return (Form 1040)?
Executive summary
MAGI (modified adjusted gross income) starts with AGI (the amount on line 11 of Form 1040) and then adds back certain deductions and excluded amounts that the IRS wants counted for eligibility tests; MAGI is not printed on Form 1040 but is computed for specific credits and limits (e.g., Roth IRA eligibility, student loan interest phaseouts) by adding items like tax-exempt foreign income, tax-exempt interest, and certain deductions back to AGI (AGI on line 11) [1][2]. Exact items added back vary by the statute or worksheet that asks for MAGI, so MAGI can differ depending on the tax benefit being measured [3][4].
1. AGI: the baseline number on Form 1040
Adjusted Gross Income (AGI) is the figure the 1040 explicitly shows (line 11) and is calculated by taking gross income and subtracting allowable “above‑the‑line” adjustments (for example, certain retirement contributions, student loan interest, self‑employment deductions) — that AGI is the starting point for most tax calculations and is what appears on your federal Form 1040 [5][4].
2. MAGI: AGI, but with specific add‑backs the IRS cares about
Modified Adjusted Gross Income is simply AGI plus certain items that the IRS or a given statute tells you to add back; MAGI is not a single universal number printed on the 1040, it’s a family of calculations used for different rules, and you must follow the worksheet or statute tied to the credit, deduction, or phaseout to know which add‑backs apply [1][3].
3. Common add‑backs that often make MAGI > AGI
When agencies or worksheets ask you to compute MAGI they commonly instruct you to add back items such as tax‑exempt interest, excluded foreign earned income, certain employer‑provided benefits, IRA conversions to Roth, and other exclusions or deductions that reduced AGI — these add‑backs are why MAGI can be larger than AGI for purposes like Roth eligibility and premium tax credit calculations [1][2][6].
4. Why the distinction matters: eligibility and phaseouts
Tax rules use MAGI because lawmakers want a stricter income test for particular benefits; for example, MAGI thresholds determine whether you can deduct traditional IRA contributions or contribute to a Roth IRA and affect phaseouts for student loan interest and certain credits — the IRS provides specific worksheets and limits tied to those MAGI calculations [1][2].
5. There is no single “the MAGI” line on 1040 — you must compute it
You will not find a labeled MAGI line on Form 1040; instead, start with line 11 (AGI) and add back the items listed in the instruction or publication for the deduction/credit you seek. Multiple reputable tax guides repeat that MAGI must be calculated manually and that the definition “depends on how the calculation is used” [5][7][4].
6. Variations and practical implications for filers
Because the set of add‑backs varies by program, the MAGI used for one purpose (say, Roth IRA contribution limits) can differ from the MAGI used to determine eligibility for another program (for example, the new deductions referenced in recent legislation); taxpayers should consult the IRS worksheet tied to the specific item rather than assume one universal MAGI [3][1].
7. Where to look for exact rules and worksheets
The IRS publishes guidance and worksheets (for example, Publication worksheets and specific forms) that tell you precisely which additions to make to AGI to arrive at the MAGI relevant to a given deduction or credit; banking and tax‑advice outlets reiterate starting with Form 1040 line 11 and following the IRS worksheet for the targeted benefit [1][2][5].
Limitations and next steps
This summary is based on available guidance in the cited tax articles and IRS material: it does not list every possible MAGI add‑back or every program that uses MAGI. For a definitive determination for your return or a particular benefit, use the IRS worksheet for that credit/deduction or consult a tax professional; available sources do not mention a one‑size‑fits‑all MAGI number on Form 1040 [1][5].