What Is Modified Adjusted Gross Income For Medicare? 
Modified Adjusted Gross Income -LRB- MAGI -RRB- for Medicare is the total of your adjusted gross income and tax-exempt interest income . These are the amounts on lines 37 and 8b of IRS form 1040 . If you file your taxes as married , filing jointly and your MAGI is greater than $ 170,000 , you will pay higher premiums for your Part B and Medicare prescription drug coverage . Singles will pay higher premiums if your MAGI is greater than $ 85,000 . The increases are done on a sliding scale . If you have both Medicare Part B and prescription drug coverage , you will pay higher premiums for each . If you have only oneMedicare Part B or Medicare prescription drug coverageyou will pay an increase only on the benefit you have . Also , in 2013 persons receiving Medicare who have a MAGI over $ 250,000 for married couples or $ 200,00 for singles , and have `` Net Investment Income '' , will pay a 3.8 % Net Investment Income Tax . For more information call Social Security at 800-772-1213 . 