Calculate your Total Daily Energy Expenditure (TDEE) — the number of calories your body needs each day based on your age, gender, weight, height, and activity level. Get targets for weight loss, maintenance, and weight gain.
This calculator uses the Mifflin-St Jeor equation, considered the most accurate BMR formula for most non-athlete adults. The formula calculates your Basal Metabolic Rate (BMR) — the calories your body needs at complete rest to maintain basic functions like breathing, circulation, and cell repair. BMR is then multiplied by an activity factor to produce your Total Daily Energy Expenditure (TDEE), which represents your actual daily calorie needs.
Male BMR: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Female BMR: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Activity multipliers: Sedentary = 1.2 | Lightly active = 1.375 | Moderately active = 1.55 | Very active = 1.725 | Extra active = 1.9
Weight: 80kg | Height: 178cm | Age: 35 | Activity: Moderate. BMR = (10×80)+(6.25×178)−(5×35)+5 = 800+1112.5−175+5 = 1742.5. TDEE = 1742.5 × 1.55 = 2,701 calories/day. To lose 1 lb/week: 2,201 calories. To gain 1 lb/week: 3,201 calories.
Weight: 62kg | Height: 165cm | Age: 28 | Activity: Light. BMR = (10×62)+(6.25×165)−(5×28)−161 = 620+1031.25−140−161 = 1350.25. TDEE = 1350.25 × 1.375 = 1,857 calories/day. To lose 1 lb/week: 1,357 calories/day.
The same 40-year-old male at 75kg, 175cm changes TDEE dramatically by activity: Sedentary = 1,944 cal/day. Moderately active = 2,525 cal/day. Very active = 2,902 cal/day. Exercise alone creates a 958-calorie/day difference — equivalent to nearly a pound of fat per week.
To lose weight, eat below your TDEE. A 500-calorie/day deficit produces approximately 1 pound of fat loss per week (since 3,500 calories ≈ 1 pound of fat). A 1,000-calorie deficit produces approximately 2 pounds per week, which is generally the recommended maximum for sustainable loss. To gain muscle, eat above your TDEE by 200–500 calories and combine with strength training. Most of the surplus should come from protein to support muscle synthesis.
The calculator suggests protein at 30% of calories (4 cal/gram) and carbohydrates at 40% of calories, with the remaining 30% from fats (9 cal/gram). These are general starting points. Protein needs vary significantly with goals: muscle building typically requires 0.7–1g per pound of bodyweight, while sedentary individuals need less. Adjust macros based on your specific health goals and consult a registered dietitian for personalized guidance.
Studies show the Mifflin-St Jeor equation predicts resting metabolic rate within 10% for most non-obese adults, making it more accurate than older formulas like Harris-Benedict. However, individual variation is significant — factors like genetics, hormonal status, and metabolic adaptation from prior dieting can cause real TDEE to differ from calculated estimates by 200–400 calories.
Several factors can stall weight loss despite a calculated deficit: metabolic adaptation (your metabolism slows in response to calorie restriction), inaccurate food tracking (most people underestimate calorie intake by 20–50%), water retention masking fat loss, or the activity multiplier being too high. Taking a diet break at maintenance calories for 2 weeks can sometimes reset adaptive metabolism.
Eating below your BMR consistently can trigger metabolic adaptation, muscle loss (your body breaks down muscle for energy), nutrient deficiencies, hormonal disruption, and fatigue. Most health professionals recommend a minimum of 1,200 calories for women and 1,500 for men, and that calorie cuts stay moderate rather than extreme.
To convert pounds to kg: divide by 2.205. To convert inches to cm: multiply by 2.54. For example, 150 lbs = 68.04 kg and 5'6" (66 inches) = 167.64 cm. You can also use our Pounds to Kilograms and Inches to Centimeters converters on this site.
A pound of muscle and a pound of fat both weigh exactly one pound. The difference is density — muscle is significantly denser than fat, so it takes up less space. This is why body composition matters more than scale weight: two people of the same weight can look and feel very different depending on their muscle-to-fat ratio.