IRMAA (the Income-Related Monthly Adjustment Amount) is an extra premium higher-income households pay on top of the standard Part B and Part D premiums. We place your MAGI in the official brackets for your filing status and total the monthly surcharges into an annual figure.

Step by step

1. We look up your MAGI in the 2026 IRMAA brackets for your filing status. The brackets are cliffs: crossing a threshold by even $1 moves you a full tier.
2. Each tier carries a fixed monthly Part B surcharge and a fixed monthly Part D surcharge, per enrolled person.
3. The annual figure is the monthly surcharges × 12 — and × 2 for joint filers, because each enrolled spouse pays their own surcharge.
4. We also show how close you sit to the next threshold, since income timing (Roth conversions, capital gains, RMDs) can push a household over a cliff.

The math

annualSurcharge = (partBSurcharge + partDSurcharge) × 12 × enrolledSpouses, with the surcharges read from the CMS bracket your MAGI lands in.

Sources & assumptions

• CMS annual Part B premium and IRMAA announcement (the fall premium notice).
• Medicare.gov — "Monthly costs for Part B" and "Monthly premium for drug plans".
• SSA publication "Medicare Premiums: Rules For Higher-Income Beneficiaries".

Note: Nothing proprietary — the brackets are public CMS data and the arithmetic is fully described.

1. This IRMAA estimate is educational only, not tax or enrollment advice.
2. Medicare determines IRMAA from the tax return filed two years earlier — this year's surcharge is set by that year's MAGI, and a life-changing event (like retirement) can qualify you for a reduction.
3. The income brackets and surcharge amounts change every year; this estimate uses the 2026 figures. Joint totals assume both spouses are enrolled in Medicare.
4. This tool is not affiliated with or endorsed by Medicare, CMS, the Social Security Administration, or any government agency.