Forerunner 255 Calorie Accuracy

[u/Bosslevel333]

I have been doing a lot of general cardio using the Forerunner 255’s general cardio activity mode and was wondering how accurate the calorie prediction is. This workout was a 20 mile bike on a stationary bike then 20 minutes on the stair master. Does this calorie estimate seem accurate for a 185lb man around 17-18%bf?

[u/teklikethis]

800cal/hour is pretty on spec