I was paid a bonus last year that put me over the 85k base for Medicare. Does SS consider that one time bonus as part of my income to raise my Medicare to over 300.00 a month?

Hi,

All of your income is considered when determining whether or not you must pay a higher than the standard amount for Part B Medicare premiums. However, in some cases Social Security can use a more recent tax year for their determination if your income has changed for certain reasons (https://secure.ssa.gov/apps10/poms.nsf/lnx/0601120001). I don't know whether or not that may apply in your case, but you may want to contact Social Security to see if you could qualify for a lower premium rate.

Best, Jerry