2025 Medicare Part B Irmaa Premium Brackets 2025. By law, medicare part b premiums must cover 25% of the costs incurred by that part of the program. In 2025, medicare part b will increase to $185.00 from 2025’s $174.70 monthly premium—a $10.30 increase from last year.

Here’s the breakdown of the 2025 part b and part d irmaa. By law, medicare part b premiums must cover 25% of the costs incurred by that part of the program.