Why Courses Change Times

A 100 m swim in a 25 m pool has four wall pushes; in a 50 m pool it has one. Every push-off is a speed boost, so fewer walls means slower times — that is why LCM times are slower than SCM, and why SCY (25 yd) is fastest of all: shorter lanes and more walls, plus yards being shorter than meters.

The Conversion Factors

USA Swimming's published factors convert by event distance: sprints scale the most (turns dominate short races), distance events the least. This calculator applies the standard buckets — sprint, middle, distance — so a 200 free converts differently from a 100 free.

Using Converted Times

Conversions are best for targets and comparisons: "I need a 2:00 in SCY to project about a 2:10 in LCM." They are averages, not predictions — individual turn skill changes the real ratio. Official records always require swimming the actual course.