Bike TSS Calculator

Bike TSS compresses duration and intensity into one load number. That makes it useful for comparing hard and easy bike sessions inside the same week, even when the rides are very different in structure.

It does not tell you whether the session was well-paced, technically good, or appropriate for your current fatigue. It is a load metric, not a complete verdict on training quality.

IF tells you how hard the ride was relative to FTP. TSS adds duration so the same IF can look very different over 45 minutes versus 4 hours. VI compares Normalized Power to Average Power and helps show how steady or punchy the effort was.

That is why this page only shows VI when Average Power is available. Without AP, you can score the stress, but you cannot honestly describe pacing variability.

Normalized Power estimates the physiological cost of variable riding. Average Power is the actual mean mechanical output. Those are related but not interchangeable.

Mechanical work in kilojoules comes from Average Power over time, not from NP. That is why the old shortcut was removed here and Work only appears when AP is entered directly.

TSS becomes more useful when it rolls into longer-term load tracking. TrainingPeaks uses daily TSS to build CTL and ATL, then contrasts them to show TSB or form.

This tool stops at single-session bike TSS, but it is designed so the number you export can plug cleanly into that wider planning model.