How it's calculated
Calories burned by 100 Jumping Jacks are computed using the ACSM formula: kcal = (MET × 3.5 × body weight kg ÷ 200) × minutes. The MET for 100 Jumping Jacks is 8. MET stands for Metabolic Equivalent — 1 MET equals resting metabolism (sitting still).
Heavier people burn more calories doing the same activity because more mass must be moved. The calculator above updates in real time as you change the weight.