How accurate are Virtual Watts?

If you do not have a smart trainer or a power meter, you can configure the app to report Virtual Watts, provided that your trainer is compatible.  Virtual Watts is a calculated estimate of power exerted based on the speed from a speed sensor and a known power curve for a given trainer. 

How Accurate are Virtual Watts?

  • Accuracy is how close the measurement is to the true value.
  • Precision is how close the measurements are to each other.
Virtual Watts is a precise, but not necessarily accurate way to measure power.  As long as the setup is consistent (same power curve settings, same tire pressure, and same resistance on the wheel), the measurements made each time will be close to each other.  In the end, this is what matters.  It is a consistently precise way to measure power and therefore, track improvement over time.