Training Load (TSS) Calculator

Calculate Training Stress Score for rides using power or heart rate data. Track training load to optimize fitness and avoid overtraining.

Results

Visualization

How It Works

TSS (Training Stress Score) quantifies training load: TSS = (seconds x NP x IF) / (FTP x 3600) x 100. One hour at FTP = 100 TSS. Intensity Factor (IF) = NP/FTP — tells you how hard the ride was relative to your threshold. Variability Index (VI) = NP/AP — tells you how steady you rode (lower = steadier). Weekly TSS guidelines: beginner 200-300, intermediate 400-600, competitive 600-900, pro 800-1200. Chronic Training Load (CTL) is a 42-day rolling average of daily TSS — your "fitness" number.