IRMAA Explained: How It Works, 2025–2026 Income Limits, and How to Control It

If you’re on Medicare (or close to it), IRMAA can be one of the most frustrating “surprise” costs in retirement.

IRMAA stands for Income-Related Monthly Adjustment Amount. It’s an income-based surcharge added to your Medicare costs when your income is above certain thresholds. It affects:

• Medicare Part B (doctor/outpatient coverage) — added to your monthly Part B premium

• Medicare Part D (prescription drug coverage) — added on top of your plan’s Part D premium

The key planning challenge: IRMAA is based on your tax return from two years ago, using a Medicare version of “income” called MAGI.