Number of months that congress had a voting majority in the Obama administration?

I'm guessing you're asking how many months the Democrats had a majority in Congress during his current term.

The 111th Congress ran from January 3, 2009 to January 3, 2011. Obama assumed office on January 20, 2009. From then until the end of the 111th, the Democrats had a majority for 23 months and 14 days. Another way to put it, 713 days or 509 weekdays.