Swim CSS calculator

Enter your 200 m and 400 m times, swum all-out on the same day (25 m or 50 m pool). The calculation runs on your device: nothing is sent.

Time for 200 m

min:s

Time for 400 m

min:s

Format “2:30” or “150” (seconds). The 400 m time must be longer than the 200 m time.

In Allure+ Your CSS is the basis for your paces and swim sessions, on iPhone and iPad.

Indicative estimate based on the Wakayoshi et al. (1993) formula. It assumes two all-out efforts and does not replace a real test or a coach's advice. Consult a professional before resuming intense training.