In 2014 the Medicare Part B rate was $104.90 monthly for most people, reports Kiplinger. The monthly premiums ranged from about $146.90 to $335.70 for senior citizens with a 2012 adjusted gross income plus tax-exempt interest income that exceeded $85,000 for single taxpayers or $170,000 for married taxpayers filing jointly.
The 2014 rates matched those of 2013, notes Kiplinger. The Part B surcharge was based on a taxpayer's 2012 income, which was the most recent tax return the government had on file for most people. Taxpayers could contest the surcharges if their incomes had decreased since then due to life-changing
events, such as losing a spouse through death or divorce or getting married. Other reasons included a taxpayer or spouse retiring, reduced work hours or losing income-producing property as a result of a disaster.