Well first you need to tell us how long the lap is so we can help you. :D
Many inches are needed to equal one kilometer; about 39,370.
Each lap in a pool is 25 meters. There are 1600 meters in a mile. 25m x 20 laps = 500 meters. You would need to swim 64 laps to make a mile. Therefore 20 laps is 0.31 miles.
You need to know the size of the track to answer this.
It depends on the pool size One lap is one length of the pool. In a 25 meter pool, you need to swim about 64 laps to the mile. In a 50 meter pool, you need to swim about 32 laps to the mile. In a 25 yard pool you need to swim about 70 laps to the mile.
32 laps Or to be exact, 32 laps plus 9.34 more meters into the 33rd lap.
1000m / length of lap in metres = number of laps. You need to specify the lap length. If, for example the length is 25m, then 1000/25 = 40 laps.