What does Medicare cost on $150k of income?

Medicare is not one price. Part B starts at $202.90 a month and rises in steps for higher incomes, and above the first threshold a separate surcharge is added to whatever you already pay for a Part D drug plan. The income-related part is called IRMAA, and at $150,000 it does not apply yet.

Here's the part that catches people out: it's a cliff, not a slope. The premium is flat right across a tier and then jumps the whole way at the boundary. From where you are, the next boundary is $218,000, and crossing it costs about $1,148 more per year. Not for the income above the line. For the single dollar that crosses it.

And the income being tested isn't this year's. Medicare looks back 2 years, so a 2026 premium is set by a return you filed for 2024. It's already filed and you can't change it. That's why a one-off event years earlier, a capital gain, a Roth conversion, selling a house, can quietly set a surcharge long after you'd stopped thinking about it.

The lookback cuts the other way too. If your income has DROPPED because you retired, stopped working, or lost a source of income, you can ask the SSA to use current figures instead by filing form SSA-44 for a qualifying life-changing event. People pay a surcharge based on their working income for two years after retiring without knowing this exists.

Planning around it means watching MAGI in the years that will be tested, not the year you enrol. A conversion or a gain that would land you a dollar over a threshold is worth splitting across two tax years, because the cliff is charged per person: a couple both on Medicare pay it twice.