Here are the breakdowns on Part B premium amounts for 2017 and 2018 thus far. New premiums could be announced, however the recent annual report of the Medicare Trustees to Congress projected no changes to standard Medicare Part B premiums.
As you can see, the actual premiums amounts are the same, but the brackets for higher income earners are changing. Beneficiaries with earnings above $133,501 as a single and $267,001 as a married couple will have increased premiums compared to what they paid in 2017. Those in the highest bracket who earn more than $160,000 as a single or $320,000 as a couple will pay $428.60 each for Part B.
In December or January, you should receive a letter from Social Security telling you what your new premium for Part B will be for 2018.
Premiums are based on income from two years prior. They are tied to Social Security Cost of Living Adjustments (COLAs). If there is a COLA adjustment that increases your Social Security benefit, then the Part B premium will usually go up.
The Social Security administration recently announced that the annual COLA for 2018 will be 2%, the biggest increase since 2012. But there have been no announcements as to changes in Part B premiums for 2018.