Formula
Calories (kcal) = MET × body weight (kg) × duration (hours)Net calories = (MET − 1) × weight × hours How it works
A MET (metabolic equivalent of task) expresses how hard an activity is compared with sitting quietly, which is defined as 1 MET — roughly 1 kcal per kilogram of body weight per hour. Brisk walking at about 4 MET burns four times as much energy per minute as resting; running at 6 mph burns nearly ten times as much.
The values here come from the Compendium of Physical Activities, a reference list researchers use to standardize energy estimates. Multiply the MET value by your weight and the time spent and you get a reasonable estimate of total calories burned, including the calories you would have burned anyway at rest.
If you are tracking a calorie deficit, the "net" figure is the fairer number to add back, because your resting calories are already included in your TDEE. Heavier people burn more for the same activity, and fitter people often burn a little less because they move more efficiently.
Frequently asked questions
Why does my fitness tracker show a different number?
Trackers combine heart rate, motion and their own formulas, and they often overestimate. Neither method is exact; use one consistently to compare workouts.
Does walking a mile burn the same as running a mile?
Running burns more per mile — roughly 1.5 to 2 times as much at typical speeds — because the bouncing motion takes more energy, though the gap is smaller than the per-minute difference suggests.