A bit of background information:
For cycling, Strava assumes that about 21% of the total energy input into the body (food consumed) is used to power the bicycle (estimated human muscle efficiency). For example, if you consume 100 kilocalories (also known as Calories), then only 21 kilocalories are used to turn the pedals. Since 1 kilocalorie = 4.184 kiloJoules, then those 21 kilocalories can produce 87.864 kJ of work on the bike. The total amount of kiloJoules of work performed during your ride can be calculated by a power meter or from Strava's estimated power data.
For running, Strava estimates calories burned using your weight, the elevation data and distance of your run. Put another way, kilocalories for a run are a function of speed (grade adjusted), weight, and moving time multiplied together with a scaling factor: Calories = average speed * 3.6 * weight * 3.413E-4 * moving timeWhere: Average speed = grade adjusted speed based in meters/secondMoving time = in seconds and based on grade adjusted speedWeight = athlete weight in kg
*Note that Strava does not use heart rate data to calculate calories burned. Additionally, Strava recalculates calories for all activities regardless of recording device used and whether your recording device already calculates calories using other means.
If aren't a cyclist with a power meter, your cycling or running calorie estimations will depend heavily on both your personal weight (plus your bike's weight for cycling) and the elevation data on your activity (which is used for estimated cycling power and grade adjusted running pace). Accurate elevation data on your activity can be significantly impacted by the quality of your barometric altimeter (for certain devices) or the quality of Strava's elevation basemap in your area.
Given the above background, fill out the survey below to help us better understand the pain-points and identify the factors involved in your calorie calculation feedback: