An Olympic size pool is 50 meters down and 25 yards across. So it depends on how the pool is divided. If you're swimming 20 laps in a 50 meter pool, you're swimming 1000 meters. If you're swimming 20 laps in a 25 yard pool, you're swimming 500 yards (about 457 meters). One lap is just there, not there and back.

Hope this helps!

See the previous post entitled, "explain the distance." Some people say that a lap is two lengths, but the overwhelming majority of serious swimmers will tell you that a lap is one way down the pool.

I swam age-group from ages 8-19, and we definitely did call a length a lap. Maybe it was a kiddie thing? Wait, our coaches did too, probably just ignorance. Didn't learn the difference until high school swimming class. Just call them, "theres" and "theres and backs"

eeek these answers are driving me crazy. so you are probably crazy too
i was a full scholarship swimmer etc etc

a length and a lap is a trip from on end of the pool to the other.
any real swimmer will tell you that.
we are not horses and they cover the track only once to make a lap anyway
back to the topic
25 yards is the length of most highschool pools and many gym pools Go ask management. They sell memberships by saying they have an olympic pool and they don't know what they are talking aabout It makes us real swimmers crazy and you guys confused.
so
4 lengths is 100 yards
a 1650 is the distance of a competitive mile ( i know because i swam it in college) its a little off or we would be stopping in the middle of the pool and that wouldn't work in a race huh
so a mile is 66 lengths
remember lengths equals laps so don't multiply anything and have a great workout
from bonnie at swimkids.net