TSS Calculator — Training Stress Score
Calculate Training Stress Score from normalised power, FTP and ride duration.
From your power meter or bike computer
How We Calculate This
TSS Formula
TSS = (Duration in seconds x NP x IF) / (FTP x 3600) x 100
Where IF (Intensity Factor) = NP / FTP
This simplifies to: TSS = (Duration/3600) x IF^2 x 100
By definition, riding at exactly FTP for one hour produces a TSS of 100.
Frequently Asked Questions
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Last updated: 2025-02-20
All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.