It's a shame that this topic is so confusing to so many.
In a nutshell, your MAGI on your 2023 taxes (that you'll be filing in the coming months) determines your IRMAA level (or lack of it) for your Social Security cost in 2025. That's the two-year factor.
Similarly, your MAGI in 2024 determines your IRMAA level in 2026. Etc., etc.
Ok. That’s what I thought. I’m selling a house in 2024 which is going to affect my Medicare rate which I’ll be eligible for in 2026 (the year I turn 65).
I wonder, what is the window to sign up for Medicare? I don’t turn 65 until the very end of the year. Could I wait to file for Medicare until 2027 (a month after turning 65) and would that change my look back period to 2025? I know, that’s wishful thinking.