TDEE Calculator – Total Daily Energy Expenditure & Calorie Deficit
What is TDEE & Why Does It Determine Weight Loss?
Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a single 24-hour cycle. It is composed of your Basal Metabolic Rate (BMR) (the base energy required to keep your vital organs functioning at rest), combined with physical exercise, daily non-exercise movement (NEAT), and the thermic effect of digested food (TEF).
The Scientific Formula: Mifflin-St Jeor Equation
Dietitians and sports physicians consider the Mifflin-St Jeor formula the gold-standard peer-reviewed equation for calculating human basal metabolic rate:
- For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
- For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Multiplying your BMR by your physical activity multiplier (1.2 for sedentary desk jobs up to 1.9 for competitive athletes) yields your exact maintenance calories. Consuming a 500 kcal deficit per day produces mathematically predictable, sustainable fat loss of approximately 1 pound (0.45 kg) per week without damaging metabolic health.
Macronutrient Breakdown for Preserving Lean Muscle
During a calorie deficit, adequate dietary protein (targeting roughly 1.6 to 2.2 grams per kilogram of body weight) is crucial to preserve lean muscle tissue so weight loss comes strictly from body fat rather than functional muscle.
Frequently asked questions
What is the healthiest calorie deficit?
A moderate deficit of 500 kcal per day (producing ~1 lb / 0.45 kg of fat loss per week) is widely recommended by clinicians. Aggressive cuts exceeding 750–1000 kcal can trigger lethargy, hormonal imbalances, and muscle wasting.
Should I eat back calories burned during workouts?
Your TDEE activity multiplier already accounts for your weekly workout expenditure. Eating extra calories on top of your TDEE target will shrink your intended deficit and stall progress.
Why does weight loss plateau after several weeks?
As you lose body weight, your body requires fewer calories to move itself, lowering your BMR and TDEE. Recalculate your TDEE every 10 pounds (4.5 kg) lost to adjust your targets accordingly.