There were four preliminary runs. The 16 fastest swimmers of all heats qualified for the two semi-finals, which were held on the same day. The eight fastest starters of both races qualified here for the final on the next day.
Abbreviations:
WR = world record, OR = Olympic record, NR = national record
ER = European record , NAR = North American record , SAR = South American record, ASR = Asian record, AFR = African record, OZR = Oceania record
PB = personal best, JWB = annual world record