In 2019, the standard premium for Medicare Part B (covering medical bills) is $135.50 per enrollee per month. However, seniors who had modified adjusted gross income (MAGI) more than $85,000 in 2017 (more than $170,000 on joint tax returns) will pay more. Monthly costs go as high as $460.50 per enrollee with 2017 MAGI of at least $500,000 or $750,000 on joint returns.