Question: how many calories do you burn if you swim 1km?
Answer: Your average swimming speed matters. The same moderate pace swum freestyle at 2 miles per hour uses up 24.51 calories over the same distance, totaling just over 490 calories for 1,000 meters. Increase your speed to 3 miles per hour, and the increased intensity burns up 47.15 calories for every 50 meters swum.