The amount of laps necessary to swim a half-mile depends on the dimensions of the swimming pool. An Olympic-sized swimming pool, however, is 50 by 25 meters.
Swimming a length of 50 meters, or half a mile, is about 16 laps. To calculate the amount of distance required to swim half a mile in non-Olympic sized pools, find the number of feet in the length of the pool. One yard equals 3 feet, and 1 meter equals 3 feet, 3 5/8 inches. Multiply that number by two, since a lap is generally considered two lengths. Then take the number of feet in the half mile, which is 2,640 feet, and divide it by the number of feet in one lap.