Modified AGI (MAGI) Calculator 2026 — Multi-Purpose
Calculate your 2026 Adjusted Gross Income (Form 1040 line 11) and the four most-cited Modified AGI variants — IRA MAGI (Roth contribution limits), ACA MAGI (premium tax credit), Medicare IRMAA MAGI (Part B/D surcharge tier), and Net Investment Income Tax MAGI (3.8% surcharge). Each MAGI uses different add-backs. Free, private, runs in your browser.
| Purpose | Your MAGI | 2026 threshold | Status |
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| Step | Amount |
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Source: IRS Form 1040 + Publication 590-A (IRA) + 26 USC § 36B (ACA PTC) + § 1411 (NIIT). Last updated: May 3, 2026.
What Is MAGI (Modified Adjusted Gross Income)?
Modified Adjusted Gross Income (MAGI) is your Adjusted Gross Income (Form 1040 line 11) with specific items added back depending on the tax provision being applied. There is no single MAGI — there are at least four common variants in 2026, each defined by its own statute. The IRA MAGI determines Roth contribution and traditional IRA deduction limits; the ACA MAGI determines Premium Tax Credit eligibility on the Marketplace; the Medicare IRMAA MAGI sets your Part B and Part D premium surcharge tier two years after; and the Net Investment Income Tax (NIIT) MAGI determines the 3.8% surtax on investment income above $200,000 single or $250,000 MFJ. Source: IRS Publication 590-A.
Because each MAGI uses different add-backs, the same gross income can produce four different MAGIs — and trigger different penalties or credit reductions. This tool computes all four side by side using your single set of inputs.
IRA MAGI vs ACA MAGI vs IRMAA MAGI vs NIIT MAGI
The four variants share AGI as a base but diverge on add-backs:
- IRA MAGI (Pub 590-A): AGI + traditional IRA deduction + student loan interest + foreign earned income/housing exclusions + savings bond interest exclusion + employer adoption benefits exclusion. Used for Roth contribution and traditional IRA deduction phase-outs.
- ACA MAGI (IRC § 36B): AGI + tax-exempt interest + untaxed Social Security benefits + foreign earned income/housing exclusions. Used for Premium Tax Credit and cost-sharing reduction eligibility on Healthcare.gov.
- Medicare IRMAA MAGI (42 USC § 1395r): AGI + tax-exempt interest. Used by SSA two years later (2026 returns affect 2028 Medicare premiums) for Part B and Part D surcharges.
- NIIT MAGI (IRC § 1411): AGI + foreign earned income/housing exclusions. Used to determine the 3.8% surtax on net investment income above the threshold.
Common Threshold Cliffs to Watch in 2026
MAGI cliffs in 2026 are sharper than most taxpayers expect. The Roth IRA phase-out for single filers begins around $153,000 and ends around $168,000 (MFJ approximately $240,000-$250,000) — final 2026 figures are set by IRS Revenue Procedure 2025-19. The Net Investment Income Tax cliff is fixed by statute at $200,000 single / $250,000 MFJ — it has never been indexed since enactment in 2013, so more taxpayers cross it every year. The Medicare IRMAA Part B cliff for 2026 is estimated above $109,000 single / $218,000 MFJ — and IRMAA is a true cliff (not phased), so $1 over the threshold can add $80+ per month to Part B alone, plus a Part D surcharge.
How to Use This Calculator for Tax Planning
Three high-leverage moves to lower your MAGI before the 2026 deadlines: (1) max your HSA — every dollar reduces AGI 1:1 with no add-back to most MAGI variants; (2) max your traditional 401(k) at work — pre-tax 401(k) contributions reduce AGI but do not add back to IRA, ACA, or NIIT MAGI; (3) tax-loss harvest before December 31 — capital losses up to $3,000 reduce AGI and all four MAGIs simultaneously. Roth conversions increase MAGI in the year of conversion — model the IRMAA two-year lookback before converting in retirement. Last updated: May 3, 2026.