What is IRMAA, and how do I avoid the Medicare premium surcharge?

Q: What is IRMAA, and how do I avoid the Medicare premium surcharge?

IRMAA (Income-Related Monthly Adjustment Amount) is the surcharge added to Medicare Part B and Part D premiums when your modified adjusted gross income exceeds set thresholds — starting at $106,000 (single) or $212,000 (MFJ) in 2026. Crossing one of the five tiers can add $1,000 to $7,000 per year per spouse to your Medicare costs. Most retirees encounter IRMAA unintentionally through Roth conversions, RMDs, or large capital gains.

Key facts

2026 IRMAA tiers (MFJ MAGI): Tier 1 starts at $212,000, Tier 2 at $266,000, Tier 3 at $334,000, Tier 4 at $400,000, Tier 5 at $750,000.
2026 single-filer thresholds are exactly half: $106,000 / $133,000 / $167,000 / $200,000 / $500,000.
IRMAA uses MAGI from two years prior — 2026 premiums are based on your 2024 tax return.
Medicare Part B base premium in 2026 is $202.90/month. Tier 1 adds $81.16/month/person; Tier 5 adds $445.93/month/person.
IRMAA is a "cliff" — going $1 over a threshold triggers the full bracket's surcharge, not a marginal rate.
You can appeal IRMAA via Form SSA-44 if you've had a "life-changing event" — retirement, marriage, divorce, death of spouse, work reduction.
Tax-exempt municipal bond interest counts in IRMAA MAGI even though it's federally tax-free.
Roth IRA withdrawals do NOT count toward IRMAA MAGI — a major planning advantage of Roth conversions before age 63.

Common follow-up questions

How much does IRMAA cost in 2026?

For a married couple, crossing into Tier 1 (>$212,000 MAGI) adds about $1,950 per spouse per year to Medicare premiums — roughly $3,900 for the household. Tier 5 (>$750,000 MAGI) adds $7,150 per spouse, or $14,300 per household. The same amounts apply to single filers at the corresponding thresholds.

Can I appeal IRMAA?

Yes — file Form SSA-44 with documentation of a "life-changing event" that reduced your income. Qualifying events: marriage, divorce, death of spouse, retirement, work-hour reduction, loss of pension, or loss of income from settlement. The SSA can recalculate IRMAA using your current year's expected income instead of the lookback year.

Does Roth conversion trigger IRMAA?

Yes — the conversion amount counts as ordinary income in the year converted, raising your MAGI two years before the IRMAA hit. Smart conversion planning targets the dollars below the next IRMAA cliff each year. A $50,000 conversion that crosses the cliff can cost $4,000+ in extra Medicare premiums two years later.

What income counts toward IRMAA?

IRMAA MAGI = AGI plus tax-exempt municipal bond interest. So Roth conversions, traditional IRA/401(k) withdrawals, RMDs, capital gains, dividends, rental income, pension income, and Social Security all count. Roth withdrawals, HSA withdrawals for qualified medical expenses, and qualified life insurance loans do not.

When does IRMAA start applying?

IRMAA applies from the moment you enroll in Medicare Part B or Part D — typically at age 65. The lookback uses your tax return from two years prior, so 2026 premiums (for someone enrolling at 65 in 2026) are based on 2024 income.

When this doesn't apply

These thresholds change each year — IRMAA is indexed to inflation but with a one-year lag. Married couples filing separately face a much harsher schedule (Tier 1 starts at $106,000 MAGI). Special rules apply if you delay Medicare enrollment because of employer coverage.

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