Variability Index Calculator
Variability Index (VI) measures how smooth (evenly paced) or variable (with frequent changes) was your power output during your ride. Enter Average and Normalized Power to get a Variability Index of your cycling workout.
Smoother pacing, stronger rides
FormBeat computes VI, IF, and TSS for every ride and shows how your pacing and training load are trending.
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“If you find yourself wishing there was just one simple resource you could rely on to fully explain, examine and guide your training, FormBeat could be your answer.”
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Related Tools
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Score a ride's training stress from duration, power, and FTP.
Intensity Factor Calculator
See how hard a ride was relative to your threshold.
FTP Calculator
Estimate your FTP from a 20-minute, ramp, or 8-minute test and get your power zones.
Power Zones Calculator
Turn your FTP into training zones with exact watt ranges.
A coach who's seen every ride you've done
Ask FormBeat's AI Coach anything - what to ride today, why a session felt flat, how to pace your next race - and it answers from your real training: your power, your history, how you're recovering. Not generic tips, but a read of what each ride actually meant and what to do next.
The guidance you'd pay a coach for - for the price of an app.
