When Are Medicare Premiums Calculated? 
If you are referring to Medicare Part B premiums - they are calculated by your IRS tax returns - 2 years prior . So if you retire in 2014 , you would sign up for Medicare A -LRB- if you have n't already -RRB- and Part B . The premium for Part B will be calculated by your 2012 tax return . In 2015 it will be calculated by your 2013 tax return , 2016 by your 2014 tax return and so on . Hope that helps ! Belinda www.myseniorventure.com/answers 805-262-7970 