Calories (or kcal) are a measure of the energy you've burned during your activity. Calorie calculations are only estimates, and there are many different ways to calculate calories.
Strava shows Calories as they were provided by our upload partners. If no value is sent, or you record with the Strava mobile app, we use our own calculations. At this time, Strava only performs calorie calculations for ride, run, walk, and hike activities. All other activity types won't display calories unless the upload partner includes the data with the activity upload.
3rd Party Calculations
There's a wide range of different algorithms and inputs that can be used to estimate Calories. We recommend contacting the 3rd party for specifics on what data they use to estimate Calories.
Unlike Strava's own calculation, changes to your Strava weight and activity elevation will not affect the Caloric total.
Changes to settings in 3rd party accounts may not be reflected in Strava.
Strava's Calculations
To calculate calories for rides, Strava uses your power output and a human efficiency coefficient. Power can be estimated by entering your weight and your bike's weight, or you can use a power meter for a more accurate measure of your power output. If you're having trouble getting your Strava Power to calculate, see How to Get Power for Your Rides.
To get calorie calculations for runs, Strava requires that you enter your weight. Calories for runs are a function of speed (grade adjusted), weight, and moving time. Multiply these together with a scaling factor, and that's the estimate.