How to Calculate Calories Burned During Exercise

Calories burned during activity are usually estimated with MET values. A MET, or metabolic equivalent, measures how hard an activity is relative to sitting still: sitting is 1 MET, brisk walking about 5, and running around 10.

The formula is straightforward: calories = MET × your body weight in kilograms × time in hours. A 70 kg person running at 9.8 METs for half an hour burns 9.8 × 70 × 0.5, which is about 343 calories.

Body weight is in the formula because moving a heavier body takes more energy, so two people doing the same workout burn different amounts. That's why calorie figures are personal, not universal.

Intensity is captured by the MET value. Walking slowly is under 3 METs; running fast is over 12. Picking the activity and pace that matches what you actually did is the biggest factor in getting a realistic number.

MET values are averages measured across many people, so the estimate is a good ballpark rather than a precise count. Your real burn depends on fitness, terrain, temperature, and body composition, and even fitness trackers only approximate it.

Use the number for comparing activities and planning — for example, feeding your exercise burn into a TDEE or calorie-deficit calculator to set a weight goal — rather than treating it as an exact measurement to eat back.