Core Insights - Medicare Part B premiums for most seniors will be $202.90 per month in 2026, but some may face significantly higher costs due to income-related adjustments [2][4] - The Medicare Income-Related Monthly Adjustment Amount (IRMAA) imposes higher premiums on retirees with incomes exceeding certain thresholds, impacting affordability [4][5] Group 1: Premium Structure - Seniors with incomes above $109,000 in 2026 will incur additional costs, with a surcharge of $81.20 for single filers earning between $109,000 and $137,000 [6] - Married joint filers will not face a surcharge until their combined income reaches $218,000, but they will still pay higher premiums [6] - For single filers earning $500,000 or more, the total Medicare Part B premium will rise to $689.90, including a surcharge of $487.00 [7] Group 2: IRMAA and Roth Conversions - IRMAA surcharges begin at an income of $109,000 for single filers, with high earners facing up to $487 extra monthly [8] - Roth IRA distributions are not counted as taxable income for IRMAA purposes, which may help avoid higher Medicare premiums [8] - However, Roth conversions are taxable events and can trigger IRMAA surcharges two years later if done after age 63 [8]