The women's 100m freestyle world record is set in Long Course Meters (50m pool). Top US high school boys compete in Short Course Yards (25-yard pool), making direct comparison complex — different pool lengths and more turns affect times significantly.
The men's 100m freestyle world record is 46.40s (Pan Zhanle, 2024 Paris Olympics). The estimated LCM equivalent for top US high school boys (NISCA All-American 45.05s SCY) is approximately 47–48s — faster than the women's LCM world record, but SCY times cannot be directly subtracted from LCM times.
LCM WR set at the Italian Open (Rome). CORRECTION: Kate Douglass 50.19s is a SHORT COURSE METERS (SCM) record set at a World Cup in a 25m pool — it is NOT the LCM world record and must not be used as the women's LCM anchor.
The women's 100m freestyle world record (LCM) is 51.68 seconds, set by Marrit Steenbergen of NED on 2026-06-27 in Rome, Italy.
Top US high school boys in the 100m freestyle swim in Short Course Yards (SCY — 25-yard pool). The NISCA All-American standard is approximately 45.05s SCY. Converting to LCM equivalent yields roughly 47–48s, which is faster than the women's LCM world record, though the pool formats are not directly comparable.
Marrit Steenbergen of the Netherlands holds the LCM women's 100m freestyle world record with a time of 51.68 seconds, set at the Italian Open in Rome on 2026-06-27.
Long Course Meters (LCM) refers to a 50-meter pool — the Olympic standard. It's more demanding than Short Course Yards (SCY, 25-yard pool used in US high school and college swimming) because athletes make fewer turns per lap and cover a longer distance per length.