IRMAA surcharges for 2028 Medicare Part B and D will be based on 2026 tax returns, with thresholds starting at $109,000 for single filers.
Medicare Part B and D premiums for 2028 will be determined by modified adjusted gross income reported on 2026 tax returns, due to a two-year lookback rule. Joint filers crossing the first IRMAA threshold by $1 face annual surcharges of roughly $2,300, while the top tier reaches nearly $13,900.
In 2026, single filers with MAGI at or below $109,000 and joint filers at or below $218,000 avoid surcharges. About 8% of Medicare Part B enrollees currently pay IRMAA adjustments. Planning strategies like Roth conversions, QCDs, and capital loss harvesting can reduce MAGI before the December 31, 2026 deadline.
A couple in their late sixties saw their combined Part B premiums double after a December 2024 Roth conversion, illustrating the lag between tax planning and premium adjustments. Most planning opportunities expire at year-end, though returns are filed in 2027.