Irmaa 2025 Formula. Once the irmaa calculations are done, cms notifies the social security administration (ssa) so we can make irmaa determinations. In 2025, the medicare irmaa brackets will be adjusted based on the income you reported two years prior, which means your 2023 income will determine your irmaa for 2025.

Monthly part b premium $ 0. You calculate irmaa by looking at your modified adjusted gross income (magi) from two years ago.