The number of calories a person burns in a day varies greatly depending on their age, sex, weight, height, and physical activity level. On average, a moderately active adult tends to require:
- For men: About 2,400 to 2,800 calories per day.
- For women: About 1,800 to 2,200 calories per day.
This includes calories burned through basic bodily functions (also known as basal metabolic rate, or BMR) — such as breathing, circulating blood, and regulating body temperature — as well as through physical activity and the process of digesting food.
More specifically, the BMR can account for about 60% to 75% of the total calories burned in a day. Physical activity can account for 15% to 30%, and the process of digesting and metabolizing food can account for about 10% of daily calorie burn.
Keep in mind that these are general estimates and individual calorie needs can vary. To get a more accurate estimate of your daily caloric needs, you can use an online calorie calculator or speak with a registered dietitian or healthcare provider.