Medicare MAGI Calculator 2026
Calculate your Modified Adjusted Gross Income (MAGI) for Medicare IRMAA tier lookup. Find your 2026 Part B and Part D premium based on your 2024 tax return — the official SSA two-year lookback used to determine Income-Related Monthly Adjustment Amounts.
How Medicare MAGI Differs from Regular AGI
Medicare MAGI starts with your Adjusted Gross Income (AGI) from Form 1040 line 11, then adds back four items: (1) tax-exempt interest (muni bond income from line 2a), (2) excluded foreign earned income (Form 2555), (3) excluded interest from US Savings Bonds used for education (Form 8815), and (4) excluded employer-provided adoption benefits. Per the Social Security Administration's official MAGI definition for Medicare, this is a stricter definition than the ACA premium tax credit MAGI. The Social Security Administration uses your tax return from two years prior to set current-year IRMAA — so 2026 Medicare premiums are based on your 2024 MAGI.
2026 IRMAA Brackets — Single and Married Joint
The 2026 standard Part B premium is approximately $185.00/month (subject to final CMS announcement). For 2026, the IRMAA tier brackets (based on 2024 MAGI) are: Single: $106,000 or less (no surcharge); $106,001–$133,000 (Tier 1, +$74); $133,001–$167,000 (Tier 2, +$185.20); $167,001–$200,000 (Tier 3, +$295.90); $200,001–$500,000 (Tier 4, +$406.90); above $500,000 (Tier 5, +$443.90). Married Filing Jointly: $212,000 or less (no surcharge); $212,001–$266,000 (Tier 1); $266,001–$334,000 (Tier 2); $334,001–$400,000 (Tier 3); $400,001–$750,000 (Tier 4); above $750,000 (Tier 5). Both spouses on Medicare pay their own surcharges — a couple in Tier 4 pays roughly $19,500 more for Part B alone over the year than a couple under the threshold. Source: CMS premium announcements.
The "Cliff Effect" — One Dollar Over Costs $1,800/Year
IRMAA brackets are cliff brackets, not marginal. Going $1 over a threshold pushes you into the next tier for the entire year. A single retiree with MAGI of $106,001 (one dollar over the floor) pays $74/month × 12 = $888 extra for Part B vs. someone at $106,000. Cross multiple tiers — say, a one-time Roth conversion that pushes MAGI from $133,000 to $167,001 — and you can add $3,500+ to annual Part B costs (Part B + Part D combined). Common cliff triggers: Roth IRA conversions, capital gains from selling a long-held home or stock, RMDs from a large traditional 401k, inherited IRA distributions, and lump-sum severance. Smart MAGI planning includes spreading Roth conversions over several years, harvesting losses to offset gains in IRMAA years, and using QCDs to satisfy RMDs without raising MAGI.
Appealing IRMAA — Life-Changing Events
You can appeal IRMAA using Form SSA-44 if you experienced a life-changing event that reduced your income: marriage, divorce, death of spouse, work stoppage or reduction (retirement counts), loss of income-producing property, loss of pension income, or employer settlement payment. The appeal uses your current-year estimated income instead of the 2-year-old return. Filing an appeal within 60 days of the IRMAA determination notice gives you the best chance of relief. Per SSA Form SSA-44, you submit estimated income, the reason code, and supporting documents (employer termination letter, marriage certificate, etc.). Routine IRMAA does not get appealed — only true life events qualify. Last updated May 2026.
Frequently Asked Questions
What is MAGI for Medicare?
Medicare MAGI = AGI (Form 1040 line 11) + tax-exempt interest + excluded foreign earned income + excluded US Savings Bond interest + excluded adoption benefits. This stricter definition is used by the Social Security Administration to determine IRMAA Part B and Part D premium surcharges.
Why does Medicare use my 2-year-old tax return?
The Social Security Administration uses your most recent finalized tax return on file — typically the return filed two years ago. So 2026 IRMAA uses 2024 MAGI. This lookback timing means a one-time income spike can raise Medicare premiums for one year before normalizing.
What are the 2026 IRMAA income brackets?
Single filers face IRMAA at MAGI above $106,000. Married joint filers face IRMAA at MAGI above $212,000. The brackets create five tiers, with the top tier (single $500K+, MFJ $750K+) adding $443.90/month to Part B plus a Part D surcharge — approximately $7,500 extra per year per person.
Can I appeal IRMAA?
Yes, file Form SSA-44 if a life-changing event reduced your income: retirement, marriage, divorce, death of spouse, loss of pension, loss of income-producing property, or employer settlement. Use your current-year estimated income on the appeal. File within 60 days of the IRMAA determination notice.
Is IRMAA a cliff or marginal tax?
IRMAA is a cliff. One dollar over a threshold pushes you into the next tier for the entire calendar year. A single retiree at $106,001 MAGI pays $888/year more than at $106,000. Smart planners aim to stay $1,000-$5,000 below each threshold to avoid accidental cliff crossings.
Does tax-exempt muni bond interest affect Medicare?
Yes. Tax-exempt interest is added back to AGI when calculating Medicare MAGI. Municipal bonds reduce federal income tax but do NOT reduce IRMAA exposure. High earners who use muni bonds to lower their tax bill may be surprised by IRMAA based on their full MAGI.