There is a lot of variables in the guess. I could give a better guess if I know the size of the plant when flowered, how big your light is, and the general health of the plant. I am still fairly new to growing, and have had only 2 real harvest, one under my 400w light(got 9.75oz.) and my outdoor plant (got about 7oz.). This was my first run in my remodled room and it hasnt finished drying yet, but my guess is 12-14oz of of 3 med sized plants(16-18"when flowered.). Feel freee to ask any questions you'd like, I'll always try to answer them the best I can, but I prefer if you do it in my grow log so it might benefit other people as well since I usually give very detailed answers.