TDEE Calculator (Accurate)
About This Calculator
Calculate your accurate Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Factor in activity level, exercise frequency, and body composition for precise calorie targets.
Frequently Asked Questions
What is TDEE and how is it calculated?
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day. It consists of three components: BMR (Basal Metabolic Rate, 60-70% of TDEE) — calories burned at complete rest for basic functions like breathing and circulation. TEF (Thermic Effect of Food, 8-15%) — energy used to digest food. EAT + NEAT (Exercise Activity + Non-Exercise Activity Thermogenesis, 15-30%) — physical activity and daily movement. The Mifflin-St Jeor equation (most accurate for most people): Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 5. Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161. TDEE = BMR × Activity Factor. Example: 30-year-old male, 80kg, 178cm, moderately active. BMR = 1,755. TDEE = 1,755 × 1.55 = 2,720 calories/day.
What are the TDEE activity level multipliers?
Activity multipliers adjust BMR for physical activity: Sedentary (office job, little exercise): BMR × 1.2. Lightly active (1-3 days/week exercise): BMR × 1.375. Moderately active (3-5 days/week exercise): BMR × 1.55. Very active (6-7 days/week hard exercise): BMR × 1.725. Extremely active (physical job + daily training): BMR × 1.9. Common mistake: people overestimate their activity level. Working out 3 times per week for 45 minutes is "lightly active" not "moderately active" — unless you also walk 8,000+ steps daily and have an active lifestyle. A desk worker who exercises 4x/week should use 1.375-1.55 depending on workout intensity. If in doubt, choose the lower multiplier and adjust based on 2-4 weeks of tracking weight changes. Every 3,500 calories over TDEE adds roughly 1 pound of body weight.
How do I use TDEE for weight loss or muscle gain?
For weight loss: eat 300-500 calories below TDEE for steady fat loss of 0.5-1 lb/week. Example: TDEE of 2,500 → eat 2,000-2,200 calories daily. Never go below BMR (typically 1,400-1,800) as this slows metabolism, causes muscle loss, and is unsustainable. For muscle gain (bulking): eat 250-500 calories above TDEE. Example: TDEE of 2,500 → eat 2,750-3,000 calories with 0.7-1g protein per pound of body weight. For body recomposition (lose fat + gain muscle simultaneously): eat at TDEE or slight deficit (100-200 below) with high protein (1g/lb). This works best for beginners, overweight individuals, or those returning after a break. Track weight weekly (same time, same conditions) — adjust calories by 100-200 if weight isn't moving in the desired direction after 2-3 weeks. Weight fluctuates 2-4 lbs daily from water, so use weekly averages.
Why is the Mifflin-St Jeor equation more accurate than Harris-Benedict?
The Mifflin-St Jeor equation (1990) is considered the gold standard for estimating BMR because it was developed using modern body composition data. The original Harris-Benedict equation (1919) was derived from a smaller, less diverse population and tends to overestimate BMR by 5-15%, especially in overweight individuals. Comparison for a 35-year-old male, 85kg, 175cm: Mifflin-St Jeor BMR = 1,748 cal. Harris-Benedict BMR = 1,870 cal (+7%). That 122-calorie difference compounds: over a month, using Harris-Benedict could lead to consuming 3,660 extra calories (≈1 lb of fat gain). However, all equations have limitations: they estimate based on population averages and cannot account for individual metabolic variation (which can be ±10-15%). For precise measurements, indirect calorimetry (breathing into a metabolic analyzer) measures actual BMR within 3-5% accuracy, available at sports medicine clinics for $100-250.
How does body composition affect TDEE accuracy?
Muscle tissue burns 6-7 calories per pound per day at rest, while fat tissue burns only 2 calories per pound. Two people weighing 180 lbs can have very different BMRs: Person A (25% body fat, 135 lbs lean mass) BMR ≈ 1,780 cal. Person B (35% body fat, 117 lbs lean mass) BMR ≈ 1,620 cal — a 160-calorie daily difference despite identical weight. Standard TDEE equations (Mifflin-St Jeor, Harris-Benedict) use total body weight and cannot distinguish muscle from fat. For more accurate estimates when body composition is known, use the Katch-McArdle formula: BMR = 370 + (21.6 × lean body mass in kg). This is especially important for very muscular individuals (bodybuilders, athletes) whose standard-equation BMR is underestimated, and for obese individuals whose BMR is overestimated. Measure body composition via DEXA scan (most accurate, $75-150), bioelectrical impedance scale (convenient, ±3-5% accuracy), or skinfold calipers (requires trained practitioner).