Calories Burned Calculator

How calories burned are calculated

This calculator uses MET (Metabolic Equivalent of Task) values to estimate calories burned during physical activity. One MET equals your resting metabolic rate, the energy you burn just sitting still. Activities are classified by their MET value: walking at 3 mph is about 3.5 METs, running at 6 mph is about 9.8 METs, and cycling at 12 mph is about 8.0 METs. The formula is: Calories = MET × weight (kg) × time (hours). This provides a reasonable estimate, though individual variation in efficiency, fitness level, and body composition can affect actual energy expenditure by 10-20%.

Understanding MET values

MET values are derived from the Compendium of Physical Activities, a comprehensive database maintained by researchers at the University of Arizona and the National Cancer Institute. The compendium contains over 800 activities with validated MET values. Light activities (1.5-3 METs) include slow walking, light housework, and stretching. Moderate activities (3-6 METs) include brisk walking, cycling at 10 mph, and swimming. Vigorous activities (6+ METs) include running, fast cycling, swimming laps, and high-intensity interval training. The higher the MET, the more calories burned per minute.

Accuracy and limitations

The MET-based calculation is an estimate, it does not account for individual differences in basal metabolic rate, exercise efficiency, terrain, temperature, or fitness level. A well-trained athlete burns fewer calories doing the same activity than a beginner because their body is more efficient. Heart rate monitors and fitness watches that use heart rate data are typically more accurate (within 5-10%) than MET-based calculations. For weight management purposes, the MET estimate is usually sufficient, but for research or clinical purposes, indirect calorimetry is the gold standard.

How to use this calculator

Enter your body weight, select the activity type, and specify the duration. The calculator will estimate total calories burned and show the equivalent in common food items (for context). Remember that the calories burned during exercise are only part of the total daily energy expenditure, your basal metabolic rate (60-75% of total), the thermic effect of food (10%), and non-exercise activity thermogenesis (NEAT, 10-15%) make up the rest. Increasing NEAT, through standing, walking, and fidgeting, can be just as effective for weight management as structured exercise.