Health Fitness
Estimate tdee with quick inputs.
What this calculator does
TDEE (Total Daily Energy Expenditure) represents the total number of calories your body burns in a 24-hour period through basal metabolism, digestion, and physical activity. Understanding your TDEE is fundamental for nutrition planning because it determines whether you'll lose, maintain, or gain weight at any given calorie level. Your TDEE comprises basal metabolic rate (60-75% of total), thermic effect of food (10%), and activity expenditure (15-30%). Individual TDEE varies significantly based on age, sex, body composition, genetics, and lifestyle. Accurately calculating TDEE enables science-based nutrition decisions rather than guessing.
How it works
The calculator estimates TDEE by first calculating your basal metabolic rate using formulas like Mifflin-St Jeor or Harris-Benedict equations that account for age, sex, height, and weight. It then applies an activity multiplier (sedentary, lightly active, moderately active, etc.) to estimate total daily expenditure. More advanced calculations incorporate body fat percentage for greater accuracy since muscle tissue burns significantly more calories than fat tissue at rest. The calculator provides a range rather than exact number, acknowledging individual variation in metabolism.
Formula
TDEE = BMR × Activity Factor. Mifflin-St Jeor BMR: Men = (10×kg + 6.25×cm - 5×age + 5); Women = (10×kg + 6.25×cm - 5×age - 161). Activity factors: Sedentary = 1.2, Lightly active = 1.375, Moderately active = 1.55, Very active = 1.725. More accurate: TDEE = (BMR × AF) + TEF (thermic effect ≈10% of calories eaten).
Tips for using this calculator
- Track your actual weight change over 2-3 weeks at a consistent calorie level to validate your calculated TDEE; adjust if weight doesn't change as predicted
- Incorporate body fat percentage if available for more accurate calculations, as two people of identical height/weight/age can have 500+ calorie TDEE differences based on muscle mass
- Account for variation in daily activity; use a fitness tracker for one week to average actual activity, rather than guessing your activity level category
- Remember TDEE decreases 10-15% when losing weight due to reduced calorie intake and slight metabolic adaptation; adjust downward periodically during extended weight loss
- Consider seasonal and hormonal variation; women's TDEE fluctuates 100-300 calories across menstrual cycles, and cold weather reduces activity-related expenditure
Frequently asked questions
How accurate is TDEE calculation, and why does it vary between calculators?
TDEE calculations are estimates with individual accuracy ±10-20%. Different calculators use different formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) and activity assumptions, producing 200-400 calorie differences. The Mifflin-St Jeor equation is most accurate for average populations. Individual metabolic variation due to genetics, gut bacteria, medication, and hormones means no formula is perfect. Use calculated TDEE as a starting point and adjust based on actual weight change over 2-3 weeks.
Why should I use body fat percentage for TDEE calculation?
Muscle tissue burns roughly 6 calories per pound daily, while fat tissue burns about 2 calories per pound. Two people weighing 200 lbs with 15% vs 30% body fat have dramatically different metabolic rates despite identical weight. Using body fat percentage (through Katch-McArdle or similar formulas) accounts for this difference, producing more accurate TDEE estimates. If you know your body fat percentage, use it; if not, basic weight-based formulas are still reasonably accurate.
Does TDEE change during weight loss?
Yes, significantly. When eating in a calorie deficit for extended periods (4+ weeks), your TDEE decreases 10-15% due to adaptive thermogenesis—your body becomes more efficient at lower calorie levels. Additionally, as you lose weight, your absolute calorie expenditure decreases simply because you weigh less. If progress stalls, recalculate your TDEE based on your current weight. This explains why 1,500 calories might produce steady loss initially but eventually becomes maintenance.
How do I know if my activity level is accurate?
Many people overestimate activity levels. Use a fitness tracker or smartwatch for one week to measure actual steps, exercise minutes, and movement. Then select your activity category based on real data: sedentary is <5,000 steps/day; lightly active is 5,000-7,500 steps; moderately active is 7,500-10,000 steps. This real-world validation prevents the common error of calculating TDEE 300+ calories higher than actual, leading to failed weight loss goals.
