Running is one of the most energy-intensive forms of exercise available. The number of calories burned depends primarily on body weight and distance — a heavier person uses more energy to move the same distance. Pace has a smaller effect than most people expect: running faster burns slightly more calories per minute but finishes the distance sooner, so the net difference per kilometre is modest. The most accurate simple formula uses the MET (Metabolic Equivalent of Task) value: Calories = MET × body weight in kg × duration in hours.

MET values for running range from about 6 for a very slow jog (over 8:00 min/km) up to 14.5+ for near-maximum sprint efforts. A 70kg runner doing a moderate 5km run at 6:00 min/km for 30 minutes burns approximately 350 kcal. The same runner walking the same distance burns only around 220 kcal — running is roughly 60% more energy-intensive than walking the same route.

Calorie calculations are estimates, not exact measurements. Individual variation in running economy, body composition, terrain, wind, and heat all affect real-world energy expenditure. Use this calculator as a directional guide for planning nutrition around training.