Calories Burned

I wish i had one... But i dont so i dont know what to input.

Here's a simple test you can do to see what amount of calories you are burning at certain HR.
Take several 6 sec readings during the next workout or two, see what the avg seems to be.

Now do a treadmill test, before you do any other workout. Perhaps warmup to the class. Need 20 min.
Set treadmill to 4 mph level and walk for 5 min.
Increase the incline for the next 5 min until you seem to be at the same HR as during the class. Take pulse or use machines HRM reading for 6 second about every 1 min.
Then spend 10-15 min at that incline or adjust as needed to maintain that same HR. Take pulse about every 2 or 3 min for 6 sec.
Notice what your incline was during the last 10 min.

Now use a walking calculator, which has been found in studies to be more accurate than HRM's for calories burned.
Gross is what MFP or a HRM would report, for purposes of eat back and feeding that workout, use NET.

http://www.exrx.net/Calculators/WalkRunMETs.html

Now you know that when your HR avg's that amount, that's how many calories you burned in that many minutes. You can break that down to cals / min for easier math later.

Retest about once a month as fitness improves.
You can also retest at several different HR levels and see the difference. Which isn't much unless the HR really changes.