MET (Metabolic Equivalent of Task) measures the energy cost of activities relative to sitting quietly (1 MET ≈ 1 kcal/kg/hour). The Compendium of Physical Activities is the gold standard source.

kcal = MET × weight (kg) × hours. So a 75 kg person running at 6 mph (9.8 MET) for 30 min burns ≈ 367 kcal.

Heart rate monitors give better personal accuracy, but our table covers 40+ common activities with research-grade MET values.