IRMAA, or Income-Related Monthly Adjustment Amount, is an additional charge added to Medicare Part B and Part D premiums for individuals with higher incomes. It’s based on your modified adjusted gross income (MAGI) from two years prior, as reported to the IRS. If your income exceeds certain thresholds, you’ll pay more for Medicare than the standard premium. These thresholds are set annually by the Social Security Administration and typically affect individuals with a MAGI above $103,000 (or $206,000 for couples filing jointly, as of 2025). The higher your income, the higher the IRMAA surcharge on top of your regular Medicare premiums.

IRMAA adjustments apply to both Medicare Part B (which covers outpatient services like doctor visits and preventive care) and Part D (prescription drug coverage). Social Security will notify you if you’re subject to IRMAA, and the extra amount is deducted automatically from your Social Security benefits or billed to you directly. If you experience a life-changing event—like retirement, marriage, or loss of income—you can appeal the IRMAA determination by submitting a form and documentation. Understanding IRMAA is important for retirement planning, as even small increases in income can push you into a higher premium bracket.