Calorie Calculator

The Calorie Calculator estimates your daily energy requirements using the Mifflin-St Jeor equation, a validated formula published in the American Journal of Clinical Nutrition. It calculates three key numbers: your Basal Metabolic Rate (BMR) — the calories burned at complete rest; your Total Daily Energy Expenditure (TDEE) — BMR adjusted for physical activity; and a personalized calorie target based on whether you want to lose weight, maintain your current weight, or build muscle. The calculator also provides a suggested macronutrient breakdown (protein, carbohydrates, and fat) to help structure your meals. For a deeper look at body composition, pair your calorie target with our BMR calculator and body fat calculator.

Step 1 — Basal Metabolic Rate (BMR): The Mifflin-St Jeor equation estimates the calories your body needs to maintain basic physiological functions. For men, the formula is BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5. For women, it is BMR = (10 × weight) + (6.25 × height) - (5 × age) - 161. These equations were derived from metabolic measurements of 498 healthy adults and are more accurate than older formulas, particularly for obese and non-obese individuals alike.

Step 2 — Total Daily Energy Expenditure (TDEE): BMR is multiplied by an activity factor to account for movement, exercise, and the thermic effect of food. Sedentary individuals use 1.2, lightly active 1.375, moderately active 1.55, very active 1.725, and super active 1.9. These multipliers originate from work by the World Health Organization and have been validated across populations.

Step 3 — Goal adjustment: For weight loss, the calculator subtracts 500 calories to create a deficit yielding approximately 0.5 kg per week of fat loss. For muscle gain, it adds 500 calories to support hypertrophy. Maintenance equals TDEE with no adjustment.

Step 4 — Macronutrient split: The default 30% protein, 35% carbohydrate, 35% fat distribution balances muscle preservation, exercise performance, and hormonal health. Protein is set at 4 calories per gram, carbohydrates at 4 calories per gram, and fat at 9 calories per gram. Use our macro calculator and protein calculator to fine-tune these targets for your specific goals.

Consider Maria, a 32-year-old woman who weighs 65 kg, stands 165 cm tall, and works a desk job but walks her dog daily and does yoga twice weekly. She wants to lose 5 kg over the next three months.

Step 1 — Calculate BMR using the female equation: (10 × 65) + (6.25 × 165) - (5 × 32) - 161 = 650 + 1031.25 - 160 - 161 = 1,360 calories.

Step 2 — Select activity level. Maria exercises lightly 1-3 days per week, so we use the 1.375 multiplier. TDEE = 1,360 × 1.375 = 1,870 calories.

Step 3 — Apply weight loss target. The calculator subtracts 500 calories: 1,870 - 500 = 1,370 calories per day. Over a week, this creates a 3,500-calorie deficit, which theoretically produces 0.5 kg of fat loss.

Step 4 — Macronutrient targets at 30/35/35: Protein = (1,370 × 0.30) / 4 = 103g. Carbohydrates = (1,370 × 0.35) / 4 = 120g. Fat = (1,370 × 0.35) / 9 = 53g. Maria can adjust these ratios based on preference — higher protein enhances satiety, while higher carbohydrates support her yoga performance.

Lose Weight: Select this if your body mass index exceeds the healthy range for your height, if a physician has recommended weight loss, or if you want to reduce body fat while preserving muscle. The 500-calorie deficit is appropriate for most people with more than 5 kg to lose. If you are already lean or experience fatigue, hunger, or strength loss, reduce the deficit to 250 calories. Weight loss should average 0.5-1% of body weight per week to minimize muscle loss.

Maintain: Use this setting when you are satisfied with your current weight and body composition, or when transitioning between bulking and cutting phases. Eating at TDEE keeps your weight stable while providing sufficient energy for performance and recovery. This is also the appropriate setting for calculating maintenance calories during diet breaks, which help restore metabolic rate and hormone levels after prolonged dieting.

Gain Muscle: Choose this if you are resistance training consistently and want to increase lean body mass. The 500-calorie surplus supports muscle protein synthesis and provides energy for progressively heavier training. Novice lifters can gain muscle faster (1-2% of body weight per month), while advanced trainees should aim for slower gains (0.25-0.5% monthly) to minimize fat accumulation. Pair the surplus with at least 1.6g of protein per kg of body weight and progressive overload in training.

Meal planning and tracking: Beyond goal selection, use the macro breakdown to structure grocery shopping and meal prep. The protein target ensures muscle preservation during weight loss or supports hypertrophy during muscle gain. Carbohydrates fuel training sessions, while fat supports hormone health. Track your intake for 2-3 weeks, measure your weight trend, and adjust calories up or down by 100-200 if progress stalls.