Active Calories represents the energy you burn through movement—walking, exercise, and daily activity—separate from your baseline metabolic needs. It is the portion of your total daily energy expenditure that you can actively influence.

Devices like Apple Watch estimate this using heart rate, motion sensors, and personal characteristics (age, weight, etc.). The number is directionally useful but not exact; depending on the activity, estimates can vary meaningfully from true energy expenditure.

For generally healthy individuals, the value of Active Calories is not precision but consistency. Tracking trends over time—how often you meet your movement goals, weekly averages, and changes in activity—is far more informative than any single day’s number. Hitting your daily target typically aligns with established physical activity recommendations.

Importantly, not all “calories burned” are equal. Different activities drive different adaptations (cardiovascular vs. strength). Active Calories is best viewed as a behavioral tool to ensure regular movement, not a metric for exact calorie balancing.