Calculate your daily calorie needs (TDEE), basal metabolic rate (BMR), and optimal protein, carbs, and fat split based on your fitness goals.
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Daily calorie needs are calculated in two steps: first your BMR (calories burned at rest) using the Mifflin-St Jeor equation, then your TDEE by multiplying BMR by an activity factor.
The Mifflin-St Jeor equation (1990) is the most accurate BMR formula for most people. For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. TDEE = BMR × activity factor (1.2 to 1.9).
Macronutrients are the three main nutrients your body needs in large amounts: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). The optimal ratio depends on your fitness goals.
For weight loss, higher protein (40%) helps preserve muscle mass during a calorie deficit. For maintenance, a balanced split (30/40/30) supports overall health. For muscle gain, higher carbs (45%) fuel intense training while adequate protein (30%) supports muscle synthesis. Fat should never go below 20% of calories as it's essential for hormone production.
To lose weight, eat 500 calories below your TDEE for ~1 lb/week fat loss, or 250 below for ~0.5 lb/week. Never go below 1,200 cal/day (women) or 1,500 cal/day (men) without medical supervision.
A moderate deficit of 500 cal/day is sustainable and preserves muscle mass. Aggressive deficits (750+) may cause muscle loss, metabolic adaptation, and are harder to maintain. Combine a calorie deficit with strength training and adequate protein (0.7-1g per lb body weight) for optimal fat loss while preserving lean mass.
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Disclaimer: This calculator provides estimates based on the Mifflin-St Jeor equation and general macronutrient guidelines. Individual needs vary based on metabolism, body composition, medical conditions, and specific fitness goals. Consult a registered dietitian or healthcare provider for personalized nutrition advice, especially if you have dietary restrictions or health conditions.
Understanding your daily energy expenditure is the foundation of any successful fitness journey. Whether your goal is weight loss, muscle gain, or maintenance, this calculator provides a science-backed starting point using the Mifflin-St Jeor Equation, currently regarded as the gold standard for estimating metabolic rate by the Academy of Nutrition and Dietetics.
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to maintain vital functions like breathing, circulation, and cell production. For most people, BMR accounts for 60-75% of total daily calorie burn. The Mifflin-St Jeor formula calculates BMR as: Men: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 5. Women: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161.
TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor ranging from 1.2 (sedentary) to 1.9 (very active). This represents the actual number of calories you burn daily. To lose weight, eat below TDEE. To gain muscle, eat above TDEE. To maintain, eat at TDEE.
Calories determine weight change, but macronutrients determine body composition. Protein (4 cal/g) is essential for muscle repair and satiety — we prioritize higher protein (40%) for weight loss to prevent muscle wasting. Carbohydrates (4 cal/g) are your body's primary fuel source, especially important for high-intensity training. Fats (9 cal/g) are vital for hormone production, nutrient absorption, and brain function — never go below 20% of total calories.
Real-world example: A 30-year-old male, 178 cm, 80 kg, exercising 3-5 days per week has a TDEE of approximately 2,500 calories. For weight loss at a 500 calorie deficit: 2,000 cal/day with 200g protein, 175g carbs, 56g fat. This creates a sustainable loss of approximately 0.5 kg (1 lb) per week while preserving lean muscle mass.
This calculator is designed for healthy adults. It may not be accurate for: pregnant or breastfeeding women (who need additional calories), elite athletes with very high muscle mass (who may benefit from the Katch-McArdle formula using body fat percentage), individuals with metabolic disorders, or children under 10. In these cases, consult a registered dietitian or healthcare provider for personalized guidance.
"Starvation Mode" is a myth — however, metabolic adaptation is real. When you lose significant weight, your body burns fewer calories because there is less mass to maintain. We recommend recalculating your TDEE every 5 kg (10 lbs) lost to ensure your calorie targets remain aligned with your current body weight. Extreme calorie restriction (below 1,200 for women or 1,500 for men) is not recommended without medical supervision.