How do you calculate calories burned?

You could go to these sites and enter the info in and take an average of the 2, or go with the lowest:
http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx
http://www.gersic.com/calories/index.php?daAge=32&daRHR=52&daAHR=148&daMinutes=27&daSeconds=0&Submit=Submit&action=1

You could go to these sites and enter the info in and take an average of the 2, or go with the lowest:
http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx
http://www.gersic.com/calories/index.php?daAge=32&daRHR=52&daAHR=148&daMinutes=27&daSeconds=0&Submit=Submit&action=1

And in case you want to see why that first link is really nice, and potentially accurate, and how accurate,

http://www.braydenwm.com/calburn.htm

The study is on this link.

That shapesense calculator will also confirm that you are using a HR that is actually valid for getting an accurate estimate.
Sadly, they based it on 220-age, instead of if you enter your true VO2max. I hated avg 162 for a couple hour bike ride, and it wouldn't tell me what the estimate was.
Braydenwm site will spit it out no matter what, so just confirm you are in correct range for using it.

I use a bodybugg to count calories

I also do P90x and when i did the P90x+ Interval (similar to plyo) It says I burnt 250-300 each time I have done it.

Also since you will be doing the weights videos soon....on average i burn 150-200 for each weight workout in p90x

Hope that helps a little

http://www.braydenwm.com/calburn.htm

this website states I burned 453

either use the lowest or an average, whatever you feel more comfortable doing.