 [ Symptoms ] how many calories are burned when swimming a mile  a mile at a moderate speed i am 225lbs and female [ Disease ] most helpful answer that would depend on several other factors like the type of stroke for instance a butterfly would burn up more calories than freestyle speed would be another factor    you burn off more if you are being chased by a shark than a leisurely swim the calorie expenditure also changes when you get in better shape a bad swimmer likely burns off more calories than someone who has a perfect stroke a round figure could be around 400 kcal but that is a very rough estimate