If you've ever tried to lose weight or build muscle, you've probably heard the phrase "calories in, calories out." But how many calories do you actually need? That's where TDEE comes in — and understanding it is the single most important step in any nutrition plan.
TDEE stands for Total Daily Energy Expenditure. It's the total number of calories your body burns in a day, including everything from breathing and digesting food to walking and exercising. Your TDEE is made up of three components:
The most accurate widely-used formula is the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics considers the gold standard for estimating BMR:
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
Your BMR is then multiplied by an activity factor:
Use our TDEE calculator to get your number instantly.
To lose weight, you need to eat fewer calories than your TDEE — this is called a caloric deficit. A deficit of 500 calories per day results in approximately 1 pound of fat loss per week (since 1 pound of fat ≈ 3,500 calories).
Example: If your TDEE is 2,400 calories, eating 1,900 calories daily should produce about 1 pound of weight loss per week. Don't go below a 750-calorie deficit — extreme restriction leads to muscle loss, metabolic adaptation, and is unsustainable.
To build muscle, you need a caloric surplus — eating more than your TDEE. A surplus of 200-300 calories per day is sufficient for most people. Combined with resistance training and adequate protein (0.8-1g per pound of body weight), this supports muscle growth while minimizing fat gain.
Use our macro calculator to split your calories into the right protein, carb, and fat ratios, and our protein calculator for your daily protein target.
Every TDEE formula is an estimate. Individual factors like genetics, hormones, gut bacteria, and NEAT (Non-Exercise Activity Thermogenesis — fidgeting, walking, standing) can cause your actual TDEE to vary by 10-15% from the calculated number.
The best approach: use the calculator as a starting point, follow the plan for 2-3 weeks, then adjust based on results. If you're not losing weight at a 500-calorie deficit, reduce by another 100-200 calories. If you're losing too fast (more than 1.5 lbs/week), add calories back.