A little more than half a lap on an outdoor track.
3 and 3/4 around a 400 m track
A standard track lap is equal to 400 meters for an outdoor track and 200 meters for an indoor track.
Tracks may have varying dimensions. A typical high school track usually surrounds a football field, which requires a minimum length of almost 110 meters. If both turns are equal, each turn of a newer 400 meter track will thus be a maximum of 90 meters long.
The track at Warinanco Park in Elizabeth, NJ is 400 meters long.
The distance of a standard running track is typically 400 meters per lap. To calculate how many laps equal 21 kilometers, you convert 21 kilometers to meters, which is 21,000 meters. Dividing 21,000 meters by 400 meters per lap gives you 52.5 laps. Therefore, it would take 52 and a half laps around a standard track to equal 21 kilometers.
The 440 yard track at my old high school (Millikan HS, Long Beach, CA), has an inner grass oval of about 215 ft x 510 ft, and an outer dimension of about 300 ft x 595 ft. (I measured from Google Maps satellite view.)
If you are in lane 1, then you must run 12 1/2 laps to equal 5k. The explanation for this is that a normal running track is 400 meters, therefore 12 1/2 laps would equal 5000 meters; i.e. 5K meters.
A 5K race is equivalent to 5 kilometers, which is equal to 5000 meters. Since a standard track is 400 meters long, you would need to complete 12.5 laps around the track to cover a distance of 5000 meters. Therefore, a 5K race would require you to run around the 400 m track 12.5 times.
5000 meters would be 12.5 laps around an Olympic size (400 meters) track.
That's only about three quarters of one straightaway
A standard running track is 400 meters, so 2 laps is practically half a mile, and 4 laps is 9 meters shy of one mile. (1 mile = 1,609.344 meters)
400 meters.