Have a Large 401(k) Balance and Approaching 62? Make Sure You Convert Before This Medicare Rule Kicks In

A $200,000 conversion at 63 that pushes MAGI to $250,000 can trigger roughly $3,895 in annual Part B surcharges, doubling for married couples. That instinct collides with a Medicare rule most conversion calculators ignore, and the collision starts at age 62.pixs4u / Shutterstock.comMedicare Part B uses a two-year income lookback. Enroll at 65, and the Social Security Administration reaches back to your tax return from age 63 to set your Income-Related Monthly Adjustment Amount (IRMAA). Every dollar converted from age 63 onward is a dollar the Medicare system will see. Run the math on a $200,000 conversion done at age 63 that pushes a single retiree's MAGI to $250,000.