Swimming approximately 64 lengths in a 25-meter pool equals one mile. If one lap equals two lengths, approximately 32 repetitions in a pool of this size are needed to complete a mile.
One mile equals 1609.3 meters. Competitive swimmers and their coaches do not use the exact mathematical calculation to determine the number of laps necessary to reach a mile. These pros and their coaches use 1650 meters as their own benchmark, a length which actually is longer than a true mile. In swimming competitions, 1650 yards is also often called a mile, which is shorter than a true a mile.