The number of calories burned by jumping jacks depends on a person's body weight and how fast they perform them. For most adults, 100 jumping jacks will burn somewhere between 100 and 200 calories.
Adults will burn roughly between one and two calories per jumping jack when performing them at a moderate intensity. Those performing jumping jacks should be aware that they are considered a high-impact exercise, as the constant jumping wears on the joints of the hips, knees and ankles. Before using jumping jacks as a substitute for other cardiovascular exercises, a physician should be consulted.
For safety, jumping jacks should be done on a soft surface and with appropriate footwear.