TSS calculator
Training Stress Score and Intensity Factor for a ride, from your FTP, ride time and Normalized Power.
Typical IF values (Andrew Coggan)
| IF | Training sessions or races |
|---|---|
| Less than 0.75 | Recovery rides |
| 0.75–0.85 | Endurance-paced training rides |
| 0.85–0.95 | Tempo rides, aerobic and anaerobic interval workouts (work and rest periods combined), longer (>2.5 h) road races |
| 0.95–1.05 | Lactate threshold intervals (work period only), shorter (<2.5 h) road races, criteriums, circuit races, longer (e.g., 40 km) TTs |
| 1.05–1.15 | Shorter (e.g., 15 km) TTs, track points race |
| Greater than 1.15 | Prologue TT, track pursuit, track miss-and-out |
TSS: an approximate guide (Andrew Coggan)
| TSS | Recovery |
|---|---|
| Less than 150 | Low: recovery generally complete by following day |
| 150–300 | Medium: some residual fatigue may be present the next day, but gone by 2nd day |
| 300–450 | High: some residual fatigue may be present even after 2 days |
| Greater than 450 | Very high: residual fatigue lasting several days likely |
Both tables are quoted from Coggan’s Normalized Power, Intensity Factor and Training Stress Score (TrainingPeaks). Coggan adds that “individuals will tend to differ in how much training they can tolerate.”
Training by power? FTP and zones Calories from power Power-to-weight chart
TSS = (seconds × NP × IF) ÷ (FTP × 3600) × 100, and IF = NP ÷ FTP, so one hour at FTP is 100. Normalized Power needs your second-by-second power file, so take it from your head unit or app; this page doesn’t estimate it. Work in kJ is exact: average watts × seconds ÷ 1000. Target TSS solves the same formula for NP. Training Stress Score®, Normalized Power® and Intensity Factor® carry the ® mark on TrainingPeaks’ pages; Pedal Brief isn’t affiliated with TrainingPeaks. Sources: Friel, "Estimating Training Stress Score (TSS)", TrainingPeaks; Coggan, "Normalized Power, Intensity Factor and Training Stress Score", TrainingPeaks; TrainingPeaks Help Center, "Training Stress Scores (TSS) Explained"; TrainingPeaks Help Center, "Variability Index (VI)"; CTS (kJ = watts x seconds / 1000).