2026 IRMAA Brackets: Medicare Part B and Part D Income-Related Surcharges

The Income-Related Monthly Adjustment Amount (IRMAA) is a surcharge added to your Medicare Part B and Part D premiums if your Modified Adjusted Gross Income (MAGI) is above certain thresholds. Medicare subsidizes about 75% of the base Part B premium for most beneficiaries; IRMAA reduces that subsidy for higher-income households, increasing the premium by a tier-based surcharge.

The official IRMAA tiers are set annually by the Centers for Medicare & Medicaid Services (CMS), typically published in the fall for the following year. The income used to determine IRMAA is your MAGI from two years prior — so 2026 IRMAA is based on your 2024 tax return, with very limited exceptions for qualifying life-changing events.

The two-year lookback is the most common source of surprise. Someone retiring in 2026 may be under the IRMAA threshold for that year — but their 2026 Medicare premium is based on 2024 MAGI, when they were still working at peak income. The reverse is also true: a large Roth conversion in 2026 can increase 2028 Medicare premiums.

The Social Security Administration applies IRMAA automatically based on IRS-reported MAGI. If your income has dropped due to a "life-changing event" (retirement, reduction of work hours, death of a spouse, divorce, loss of pension, and a small set of others), you can file Form SSA-44 to request that IRMAA be recalculated using your expected current-year income instead of the two-year-prior figure.

MAGI for IRMAA purposes is your Adjusted Gross Income (AGI) plus tax-exempt interest (from municipal bonds) plus certain foreign-earned income exclusions. Notably, MAGI for IRMAA does not add back pretax retirement account contributions (those already reduce AGI) and does include the taxable portion of Social Security benefits, traditional IRA withdrawals, Roth conversions, capital gains, and dividends.

Because MAGI includes Roth conversions and realized capital gains, a single large tax-year event can push a household across one or more IRMAA tiers, each of which is a step function (not a marginal bracket). Crossing a threshold by one dollar creates the full surcharge of the next tier.

IRMAA tiers are cliffs, not smooth slopes. If the top of a tier is $212,000 (joint filer, illustrative), then MAGI of $212,001 puts you entirely into the next tier for the year. That one dollar over could cost a couple hundreds to thousands of dollars in extra Medicare premiums for the year, per spouse.

Practical planning implications: cluster Roth conversions in years you are already in a higher bracket for other reasons; avoid dripping conversions just over a tier boundary; be deliberate about capital gain realizations in the two years before Medicare eligibility; treat the IRMAA surcharge as a real marginal cost when evaluating any income-increasing decision near the tier boundaries.