Why exercise-calorie estimates vary
Activity-based calorie estimates are model outputs, not direct measurements. A MET value (metabolic equivalent of task) describes the energy cost of an activity relative to rest; estimates commonly combine an activity value, body mass, and duration. Different speeds, terrain, intensity, fitness, and measurement methods can change the result.
Use the number as a rough comparison
A 30-minute walk and a 30-minute run do not have the same estimated energy cost, and two people doing the same activity may not expend the same amount. Activity labels also represent broad categories rather than precise intensity measurements.
The result should not be used to decide how much to eat or to compensate for food. This calculator does not measure your metabolism and may differ from fitness-watch estimates. If you are using activity data for a medical or training plan, discuss what is appropriate for you with a qualified professional.
Tips for accurate results
Most estimates multiply a MET value for the activity by your body weight in kilograms and the time in hours. Pick the activity that best matches your real effort, since brisk walking and a leisurely stroll have different MET values. Heavier people burn more in the same time doing the same activity.
Common mistakes and limits
Fitness trackers and calculators can disagree, and both are approximations. Treat the figure as a rough guide rather than an exact allowance, and avoid automatically eating back every estimated calorie. Individual differences in efficiency, terrain, and fitness all shift the real number.