RMDs and Roth conversions: California-specific retirement planning
How Required Minimum Distributions and Roth conversions interact with California income tax and Medicare IRMAA — for Contra Costa County retirees.
Retirement planning gets more interesting after 60. RMDs, Roth conversions, Social Security timing, and Medicare IRMAA thresholds all interact — and California adds its own twist.
The Roth conversion window
The 'sweet spot' for many retirees is the years between retirement and RMD age. Income is low, so filling up the lower federal tax brackets with Roth conversions can save significant tax later.
California's angle
California taxes Roth conversions as ordinary income the year you convert (~9.3% at moderate brackets). That doesn't kill the strategy — but it changes the math. We model federal and California together.
IRMAA — the Medicare cliff
Modified AGI over specific thresholds triggers higher Medicare Part B and D premiums two years later. A Roth conversion that pushes you over is expensive in a way most calculators miss.
How we plan
We build a multi-year projection — usually 5 to 10 years out — that shows Roth conversion amounts, RMD timing, Social Security start dates, and IRMAA thresholds side by side. Then we decide together.