Back to tools

🏊 Critical Swim Speed

Determine your anaerobic threshold in swimming

CSS Calculator

Use your 200m and 400m times to determine your Critical Swim Speed

🏊

Swimming

Critical Swim Speed (CSS)

Format: mm:ss
Please enter a valid time (mm:ss)
Format: mm:ss
Please enter a valid time (mm:ss)
Your CSS
--:--
/100m
Estimated ADC : -- m

What is Critical Swim Speed?

The Critical Swim Speed (CSS) represents your anaerobic threshold in swimming. It is the maximum pace you can maintain for about 30 minutes without excessive lactate accumulation.

This calculator uses the Wakayoshi model, based on two timed tests (200m and 400m) to determine your critical pace. This method is scientifically validated and widely used by swimming coaches worldwide.

How to use this calculator?

  1. Perform a timed 200m swim test (maximum effort)
  2. After full recovery, perform a timed 400m swim test (maximum effort)
  3. Enter your times in the calculator in mm:ss format
  4. Your CSS sera affichée en allure par 100m

Why calculate your CSS?

CSS is essential for:

  • Calibrating your pool training zones
  • Optimizing your swimming technique
  • Tracking your progress over weeks
  • Planning your interval sessions precisely

💡 BPC Tip : Perform these tests every 6-8 weeks to track your progress. For a personalized swim training program, check out our triathlon coaching offers.

Disclaimer

Tool provided for informational and educational purposes. Results are estimates. Does not replace medical advice or personalized coaching.