Swimming Training Books

CSS Calculator

Calculate Critical Swim Speed with our handy calculator


Calculate your CSS

Critical Swim Speed (CSS) is an effective tool to measure swimming speed improvement over time and predict time to complete larger distances.

Critical Swim Speed is an estimate of your pace over a long distance.

It's calculated by comparing your 200m time trial to your 400m time trial.

Want a printable workout to help you find your CSS?

CSS Workout