BIKRAM- 90 minutes

I looked up averages online for how many calories people burn during a session, which ranged from 300-500, and then just created a workout on mfp I do Moksha, which is similar to Bikram, but more fun because instructors have creative license over the 26 postures to make it interesting every time, so I underestimated the calories burned at 400/session just in case. Not very scientific, but it's working for me.