Thank you, Dragonchilde. I knew that regular strength training didn't burn a lot of calories but since P90X keeps me in my target heart rate zone the entire time I'm doing it I was pretty sure I needed to count it as strength and cardio, but didn't know where to begin.
But problem is solved - they actually have a personal calorie burn calculator for each of the different workouts, on their site: p90xcalories.com/
for anyone else who may be using their workouts for all or part of their physical activity. Thanks again!