Calorie Calculator

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a day, including your Basal Metabolic Rate (BMR) plus calories burned through physical activity and the thermic effect of food. This calculator uses the Mifflin-St Jeor equation to estimate BMR, then multiplies it by an activity factor to determine TDEE. The Mifflin-St Jeor equation has been shown to be the most accurate predictive equation for estimating BMR within 10% of measured values in most healthy adults (Source: American Dietetic Association, Journal of the American Dietetic Association, 2005).

To lose weight, you generally need to eat fewer calories than your TDEE. A moderate calorie deficit of 500 calories per day below your TDEE typically results in approximately 1 pound (0.45 kg) of weight loss per week. A milder deficit of 250 calories per day leads to about 0.5 pounds per week and may be more sustainable long-term. It is generally not recommended to eat fewer than 1,200 calories per day for women or 1,500 calories per day for men without medical supervision, as very low calorie diets can lead to nutrient deficiencies and muscle loss (Source: National Institutes of Health, Dietary Guidelines for Americans, 2020-2025).

Basal Metabolic Rate (BMR) is the number of calories your body needs at complete rest to maintain basic life-sustaining functions like breathing, circulation, nutrient processing, and cell production. It accounts for roughly 60-75% of your total daily calorie burn. TDEE includes your BMR plus additional calories burned through physical activity (15-30% of total expenditure) and the thermic effect of food, which is the energy needed to digest and process nutrients (about 10% of total expenditure). Your TDEE is always higher than your BMR (Source: National Academy of Sports Medicine, Essentials of Personal Fitness Training).

The Mifflin-St Jeor equation is considered the most reliable predictive equation for estimating BMR in healthy, non-hospitalized adults. Studies show it predicts measured BMR within 10% in most individuals. However, individual calorie needs can vary based on factors this calculator does not account for, including genetics, body composition (muscle-to-fat ratio), hormonal factors, medications, and metabolic conditions. The activity multipliers are general estimates and may not precisely match your actual energy expenditure. For the most accurate assessment, consult with a registered dietitian or healthcare provider who can consider your full medical history (Source: Mifflin et al., American Journal of Clinical Nutrition, 1990).