What is the standard swimming pool length for lap swimming?

Length of a Lap Pool

A common lap of a pool is 50 meters internationally.

Swimming competitions are generally held in 50m pools. Many colleges or well equipped facilities have pools that are 50 meters.

A lap can be either 25 meters or 50 meters. In the Olympics and major National events they swim 'long course' events which means the pool is 50 meters in length. However, there are still short course swim meets like 'Fina' and the pool is only 25 meters.

In America there are also lots of yard pools both in 25 yard length (short course) and 50 yard length (long course) varieties