CRITICAL SWIMMING SPEED CALCULATOR
Race estimates and training zones from 2 hard efforts
This calculator not only helps calculate CSS using two distances of your choices but also gives you pacing for tempo trainers in different pool lengths, race finishing time estimates, and training zones.
How to use this calculator
Enter two set distances (200/400 is standard, but 100/500 may work even better). If you struggle on long distances or are very slow you can choose shorter distances. Ideally something where you are able to go fast, and a distance where pacing, and breathing is more important.
You will get your critical swimming speed (css) as well as a balanced score (should you work more on the shorter distances, or on longer sets), as well as pacing on different pools, or with a tempo trainer, and recommended zones with rest durations.
If you are a novice swimmer, disregard the zones, and focus on using calculator just to see improvements over the first few months of training.
The pace time prediction columns shows your current prediction, and predictions if endurance changes