Calories burned?

Samana06

I am a substitute teacher at a preschool. I would like to know what I should use to calculate how many calories I've burned during my 4.5 hours of work. Yesterday I was with the babies ... and it was like herding cats! The longest I sat down was the 15 minutes it took to feed the youngest child, didn't even have time to eat myself. The rest of this week I will be with the 3 and 4 year old group, there's a little more down time, but I do spend the majority of the time on my feet and in motion. I've been using walking leisurely pace, and light to moderate cleaning... but I would like something a little more accurate! Thanks!