To be honest it doesn't say anywhere but I remember having around 10GB of free space and all I pretty much have on here is pictures and a movie. Now I'm low on memory though.
Each part listed the download size, but nonetheless, you must have something else going on there. Have you reset the phone to factory since the update?
The lollipop update was about 386 MB. Before i updated i looked and saw 715 MB. That other 300 plus MB came from LG's and Verizon's bloatware.
I deleted a movie and it went away. I guess I don't have that much space after all. I noticed on the Google play reviews that it completely took up someone's memory. I figured I had the same problem. My bad.