Let's see.... My water bottle is 16.9 oz. I'm guessing it's a regular sized one. 8 ounces = one cup. So, just over 2 cups. :)
8 oz=1 cup depending on your water bottle size it could be 2.5 in most cases check out http://funadvice.com/r/15u7dj6romv
8 ounces,can hold 1 coup and 16.9 can hold little more the 1 and half,just i tryed wit my bottle...:)
i'll say 2 1/2