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Calculate your Basal Metabolic Rate (BMR), daily calorie requirements, and recommended macro breakdown based on your age, height, weight, activity level, and fitness goals.
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Understanding Calories and Nutrition
What Is BMR and Why Does It Matter?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and cells functioning. It accounts for 60–75% of daily calorie expenditure. BMR is calculated using the Mifflin-St Jeor equation, which factors in your weight, height, age, and biological sex. Knowing your BMR is the foundation for any nutrition plan.
TDEE and Activity Levels
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. A sedentary person (desk job, little exercise) multiplies by 1.2, while a very active person (hard exercise 6–7 days/week) multiplies by 1.725. Your TDEE represents the total calories you burn in a day. To lose weight, eat below your TDEE; to gain, eat above it. A deficit or surplus of about 500 calories per day results in roughly 1 pound of change per week.
Macronutrient Breakdown
Calories come from three macronutrients: protein (4 cal/gram), carbohydrates (4 cal/gram), and fat (9 cal/gram). A balanced diet for most adults includes 25–35% protein, 40–55% carbohydrates, and 20–35% fat. Protein supports muscle repair and satiety. Carbs fuel brain function and exercise. Healthy fats support hormones and nutrient absorption. Adjusting these ratios helps optimize for specific goals like muscle building or endurance training.