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Training Load (TSS) Calculator
Training Stress Score puts a single number on how hard a session was, combining duration and intensity. Use it to balance hard days, easy days, and recovery.
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Estimate from effort, or calculate exactly from power.
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Last updated: June 2026Reviewed by: Bryan Collins, founder
How this calculator works
Training Stress Score is estimated as duration in hours × intensity factor² × 100. In effort mode the intensity factor comes from a preset for the session type; in power mode it is your normalized power divided by FTP.
Assumptions
- • Intensity factor reflects the whole session
- • Standard TSS formula and ratings
Limitations
- • Effort-mode presets are approximations
- • TSS does not capture all sources of fatigue
Who this is for
- • Cyclists and triathletes tracking training load
- • Athletes balancing hard and easy days
- • Anyone planning recovery around big sessions
Who this is not for
- • Sports without a power or intensity reference
- • Replacing a full training-management platform
References
Related Articles
Continue exploring our comprehensive triathlon resources
Training Load (TSS) Calculator FAQ
Scientific References
Allen H, Coggan A. Training and Racing with a Power Meter.
Reference for normalized power, intensity factor, and TSS