The 2026 IRMAA cliff adds $74.40 a month to Medicare Part B premiums the moment single filers cross $109,000 of income — and the lookback uses your 2024 tax return
A retired teacher in suburban Ohio who reported $108,900 of modified adjusted gross income on her 2024 tax return will pay $202.90 a month for Medicare Part B in 2026. Her former colleague down the street, who reported $109,100 after a modest Roth IRA conversion, will pay $284.10. That $200 gap in annual income triggers…