MAGI for ACA purposes is modified adjusted gross income: the income figure the Marketplace uses under IRC Section 36B to determine APTC eligibility, CSR tier, and the Medicaid boundary. For most W-2 clients it is close to their adjusted gross income. For self-employed clients it is net profit after deductions, not gross revenue. The distinction costs clients real money when brokers get it wrong at intake.
Key Takeaways
- MAGI for ACA is AGI plus three items added back: non-taxable Social Security benefits, tax-exempt interest, and foreign income excluded from US taxes. For most domestic W-2 clients, MAGI is very close to AGI.
- Self-employed clients owe their net profit figure from Schedule C or Schedule F, not gross revenue. A $90,000 revenue year with $35,000 in deductible expenses produces $55,000 in ACA-countable income.
- The self-employed health insurance deduction reduces AGI and therefore reduces ACA MAGI, which can increase APTC. Brokers who walk through this deduction at intake help clients avoid overpaying.
- Traditional IRA contributions reduce AGI. Unlike Medicaid MAGI rules, ACA MAGI does not require adding them back, so they genuinely reduce the income figure used for subsidy calculation.
- Household MAGI is the sum of MAGI for all members of the tax household who are required to file a return. A spouse returning to work mid-year adds their projected income to the household total.
MAGI starts with AGI
Modified adjusted gross income begins with a client's adjusted gross income from their federal tax return. AGI is gross income minus above-the-line deductions: 401(k) contributions, student loan interest, the deductible portion of self-employment tax, and the self-employed health insurance deduction, among others. For a W-2 client with no unusual income sources, AGI is often the only figure a broker needs to understand.
Three items are then added back to AGI to arrive at ACA MAGI:
- Non-taxable Social Security benefits
- Tax-exempt interest income (such as interest on municipal bonds)
- Foreign earned income and foreign housing costs excluded under IRC sections 911, 931, or 933
That is the full list for ACA purposes. The Marketplace does not add back IRA deductions, student loan interest, or education-related deductions, unlike some Medicaid MAGI calculations. A broker who imports Medicaid rules into an ACA enrollment overstates the client's income.
What counts and what does not
| Income item | Effect on MAGI | Note |
|---|---|---|
| W-2 wages and salaries | Yes | After pre-tax benefit deductions like 401(k) contributions. |
| Net self-employment income (Schedule C/F) | Yes | Profit after business deductions. Gross revenue is not the right number. |
| Self-employed health insurance deduction | Reduces MAGI | Above-the-line deduction that reduces AGI. One of the few clear levers available. |
| Taxable Social Security benefits | Yes | The taxable portion is included in AGI and counts. |
| Non-taxable Social Security benefits | Added back | Must be added to AGI even if not otherwise taxable. Common among clients near the Medicaid boundary. |
| Tax-exempt interest (e.g., municipal bonds) | Added back | Municipal bond interest does not appear in AGI but is added back for ACA MAGI. |
| Traditional IRA contributions | Reduces MAGI (ACA) | Unlike Medicaid MAGI, ACA MAGI does not add IRA deductions back. They genuinely reduce ACA income. |
| Capital gains from asset sales | Yes | Both short-term and long-term gains are included. A property sale can spike MAGI significantly. |
| Rental income (net of deductible expenses) | Yes | Net rental income on Schedule E. Depreciation deductions reduce the taxable amount. |
| Alimony received (pre-2019 divorce decrees) | Yes | Alimony under pre-2019 agreements is includable in AGI. Post-2018 agreements are not. |
Illustrative. Tax treatment of specific income types depends on individual circumstances. Clients should confirm with a tax professional.
The self-employed MAGI trap
The most common MAGI error brokers see is a self-employed client reporting their gross business revenue as income. It is an understandable mistake: bank statements show revenue, the client knows what came in, and gross revenue is the number that feels real to them. The Marketplace needs something different.
ACA MAGI counts net self-employment income from Schedule C or Schedule F. A sole proprietor who brought in $90,000 in gross receipts and spent $40,000 on deductible business expenses reports $50,000 in Schedule C net profit. That $50,000 is the base figure going into the MAGI calculation, not the $90,000. An intake conversation that captures gross revenue and stops there misses $40,000 in deductions and may significantly underestimate APTC eligibility.
Example: a 48-year-old freelance consultant with $90,000 in gross receipts, $40,000 in Schedule C deductions, a $7,000 self-employed health insurance deduction, and no other income. MAGI would be approximately $43,000. At a household size of one, that puts this client around 337 percent of the 2026 FPL, well within APTC range. A broker who captures $90,000 as income places the same client at nearly 700 percent FPL, potentially showing no subsidy at all.
Illustrative example. Actual net income, deductions, MAGI, FPL percentage, and APTC depend on individual tax circumstances and the specific plan year.
For a full walkthrough of self-employed income at intake, read ACA Marketplace enrollment for self-employed and 1099 clients.
Social Security and the non-taxable add-back
Clients receiving Social Security benefits have an additional layer to sort out. Social Security benefits that are taxable already appear in AGI. Benefits that are not taxable do not appear in AGI, but the ACA requires them to be added back to arrive at MAGI.
Whether Social Security is taxable depends on the client's combined income. Clients with income below roughly $25,000 (single) or $32,000 (joint) typically pay no tax on Social Security. Those clients still owe the non-taxable benefit amount in their ACA MAGI calculation. Near the 100 to 138 percent FPL range, the difference between including and excluding Social Security benefits can move a client across the Medicaid boundary in an expansion state. Get this right before the quote, not at tax time.
MAGI and the FPL ratio
The reason MAGI matters so much for ACA work is straightforward: every subsidy calculation reduces to household MAGI divided by the federal poverty level for the household size. The resulting percentage determines APTC eligibility, CSR tier, and whether the client qualifies for Medicaid in expansion states. A 5 percent shift in the FPL ratio can cross a CSR boundary or eliminate APTC entirely at incomes above 400 percent FPL before the enhanced subsidy provisions.
Most quoting tools, including Quotit and QuoteTurbo, display the FPL percentage once income and household size are entered. The displayed percentage is only as accurate as the income figure the broker supplies. The tool is arithmetic; the income conversation is the broker's job.
For the full FPL table and how the ratio connects to specific subsidy thresholds, read what is the federal poverty level and how does it affect your ACA subsidy.
Projecting annual MAGI when income varies
The Marketplace uses projected annual MAGI, not last year's tax return. For clients with variable income, freelancers, or those who started or left a job mid-year, the broker needs to help construct a reasonable annual projection.
A practical approach: start with the most recent three months of net income, annualize it, then adjust for anything expected to change. A client who started a new freelance contract in April and expects it to continue should project forward from that rate. A client with seasonal income should estimate the full year across high and low periods. The projection does not need to be perfect. It does need to be reasonable and defensible if CMS asks for verification.
For eligibility conditions beyond the income calculation, including employer coverage affordability rules and Medicaid interaction, read do I qualify for an ACA subsidy: 2026 income limits and eligibility.
FAQ
Questions brokers and clients ask about MAGI and ACA subsidy eligibility.
Does gross business revenue count as ACA income or just net profit?
Net profit. The ACA Marketplace counts net self-employment income from Schedule C or Schedule F, not gross receipts. A sole proprietor with $120,000 in revenue and $60,000 in deductible business expenses has $60,000 in self-employment income for ACA purposes. That figure then gets reduced by the deductible portion of self-employment tax and the self-employed health insurance deduction before becoming part of MAGI.
Is MAGI for ACA the same as MAGI for Medicaid?
The base definition overlaps, but the rules differ in one important area. Both require adding back non-taxable Social Security, tax-exempt interest, and excluded foreign income. Medicaid MAGI additionally requires adding back student loan interest deductions and some other deductions. ACA MAGI does not add those back. A broker who uses Medicaid MAGI rules for an ACA enrollment will overstate the client's income and potentially underestimate APTC.
Does a large one-time capital gain affect ACA MAGI?
Yes. Capital gains are included in AGI and count toward ACA MAGI. A client who sells a rental property mid-year and realizes a $50,000 gain will see that amount reflected in their projected annual MAGI. If they received APTC earlier in the year based on a lower projected income, they will reconcile the difference on Form 8962 at tax time. Brokers should discuss any anticipated large asset sales at intake or during annual renewal calls.
How does household MAGI work for a married couple filing separately?
Married individuals who file separately generally do not qualify for the premium tax credit, with narrow exceptions for victims of domestic abuse or spousal abandonment. The ACA assumes a married couple files jointly for purposes of subsidy eligibility. Clients who file separately for other tax reasons should confirm with a tax professional before projecting their APTC eligibility.
What counts as household income for the ACA beyond the primary applicant?
Household income for the ACA includes the MAGI of the taxpayer, the taxpayer's spouse if filing jointly, and any dependents who are required to file a tax return. A 20-year-old dependent who earns $20,000 from a part-time job and is required to file adds that income to the household calculation. A 16-year-old with no filing requirement does not. Understanding who is in the tax household matters as much as knowing what counts as income.
