The number of calories burned swimming varies based on sex, body weight and the amount of time spent swimming. A 140-lb. female burns 580 calories per hour swimming, while a 175-lb. man burns 730 calories per hour swimming, notes MedicineNet.
Swimming is a strenuous activity that burns the same amount of calories as playing football or jogging a 9-minute mile, states MedicineNet. To calculate the exact number burned, an individual must divided body weight by either 140 or 175, based on sex, and then multiply this number by the number of calories burned for that weight. This gives the approximate number of calories the individual burns while swimming.