Keeping Track of Calories Burnt

I just completed my first day of 30 Day Shred, lets just say I am not as fit as i thought I was...IT HURTS!!! I was just trying to fill in my workout for the day but it is only calculating i burnt 129 calories and it only records for the cardio. I know the real way to calculate how many calories you burn is a heart rate monitor but i am just wondering if anyone else is having this issue. is there any one who is about 5`3 and 140 lbs and doing this that could tell me roughly how many calories you burnt.