One mile is equivalent to swimming 66 lengths or 33 laps in a standard pool. A standard short course pool in the United States is 25 yards long. A long course pool is 50 yards.
A swim lap means swimming from one end of the pool to the other and back again. Swimming burns calories at a rate according to body weight and metabolism, the swimming speed, and the technique, rather than distance. For instance, during one hour, a 130-pound person burns approximately 590 calories freestyle swimming at a fast speed, while a 205-pound person burns approximately 931 calories swimming in the same manner.