Swimming pace is measured in time per 100 metres — the standard unit used by coaches, training plans, and competitive swimmers worldwide. Unlike running, where pace per kilometre is common, swimmers work in 100m units because a standard lap in a short-course pool is 25m (4 laps = 100m) and in an Olympic pool is 50m (2 laps = 100m). Knowing your pace per 100m lets you compare across pool sizes and predict race times for any distance.

Pace varies significantly by stroke. Freestyle is the fastest stroke — elite men swim sub-47 seconds per 100m. Breaststroke is the slowest — even elite swimmers are around 57–65 seconds per 100m. Backstroke and butterfly fall in between. This calculator includes world record references for each stroke so you can benchmark your pace against the best in the world.

For training, pace is used to set interval targets. A common workout structure is "200m at 1:45/100m pace with 20 seconds rest" — meaning each 200m rep should be completed in 3:30. This calculator generates finish times for all standard race distances (50m to 1500m) from your pace, making it easy to translate training data into race predictions.