One dollar of 2024 MAGI over the line adds a full year of Medicare surcharges. See the line before you cross it.
2026 tier after the change
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Next IRMAA threshold
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USD MAGI
Dollars left before that line
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USD
Cost of crossing it, household, a year
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USD
2026 surcharge before the change
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USD a year
2026 surcharge after the change
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USD a year
Dollars to the next line Shows exactly how many dollars of MAGI are left before the next 2026 IRMAA threshold, so a Roth conversion or capital gain can be sized under it.
Cost of crossing, per household IRMAA is a cliff, not a phase-in: one dollar over triggers the whole tier. This prices that dollar in Part B plus Part D for one or two people on Medicare.
Single, joint and separate brackets Married filing separately skips four tiers and lands on the 649.20 Part B rate above 109,000, which general calculators get wrong.
Part D surcharge counted Most free tables price Part B only. The Part D adjustment adds 14.50 to 91.00 a month per person and is billed even on a Medicare Advantage drug plan.
Scenario export (paid) Writes every scenario you ran to a .csv you keep with the tax file, as the working paper behind the conversion amount.
Deadline alarm (paid) Sets a browser alarm ahead of the date you choose, for the SSA-44 life-changing-event filing or the 31 December conversion cut-off.