Pick an activity, enter your weight and duration — and see exactly how many calories you burn, based on published MET (Metabolic Equivalent of Task) values.
This calculator uses the standard MET-based formula: Calories = MET × weight (kg) × duration (hours). MET (Metabolic Equivalent of Task) is a standardised measure of how much energy an activity requires relative to sitting quietly. Sitting has a MET of 1.0; walking briskly is around 3.5–4.0; running at moderate pace is around 9–11.
MET values are drawn from the Compendium of Physical Activities, first published by Ainsworth et al. in 1993 and updated in 2011. The compendium lists over 800 activities and their associated MET values. These values represent the average calorie expenditure for a given activity at a given intensity — individual variation (fitness level, body composition, efficiency of movement) means your actual burn may differ by 15–20%.
Calories burned scales directly with body weight — a heavier person burns more calories doing the same activity for the same duration. Two people running for 30 minutes at the same pace: a 60 kg person burns roughly 300 kcal while a 90 kg person burns around 450 kcal — 50% more for 50% more body mass.
MET-based estimates are reasonably accurate for moderate activities in average-weight adults — typically within 15–20% of measured calorie expenditure. Accuracy decreases for very high-intensity activities, activities requiring significant skill (where efficiency varies widely), and for people who are significantly above or below average fitness. Wearable fitness trackers use similar methods, often augmented with heart rate data, and typically achieve similar accuracy.
The formula calculates total energy expenditure for the activity, which includes the baseline metabolic rate for that period. To find only the "extra" calories burned beyond what you'd burn resting, subtract approximately 1 MET worth of calories. In practice, the difference is small for short sessions and most people don't need to make this adjustment.
Running has a much higher MET value than walking — roughly 9–11 compared to 3–4 for brisk walking. Although you cover more ground per minute when running, the main driver is simply that running requires more energy per unit time. Over the same distance (not time), walking and running burn surprisingly similar amounts — the time difference is most of the gap.