What is TDEE?

Your  TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a 24-hour period. It includes your  BMR (calories burned at rest), calories used for digestion, and calories burned through activity—both exercise and daily movement. Understanding your TDEE helps you calculate how many calories you need to lose, maintain, or gain weight [1], [2].

What males up your TDEE?

1. Basal metabolic rate (BMR)
   Your BMR is the biggest part of TDEE. It’s the energy your body uses at rest to power essential functions like breathing and circulation.
   
   How it’s calculated: BMR is based on core physical metrics, including your age, gender, height, and weight [3].
   
2. Physical activity
   This is the most variable part of TDEE, encompassing all the calories burned from movement [2].

   
   Exercise activity thermogenesis (EAT):

   Calories burned during intentional, structured exercise (like running or lifting weights).
   
   Non-exercise activity thermogenesis (NEAT):
   Energy used for all other daily movements, such as fidgeting, walking to the car, 
and household chores.
   
   Impact:
   A more active lifestyle directly translates to a higher TDEE.
   
3. Thermic effect of food (TEF)
   This is the energy cost of digesting, absorbing, and processing the food you eat [4].

Common multipliers for activity levels

Why TDEE matters — energy balance & body weight

• Your weight stays stable when calories in ≈ calories out. [5]
• To lose fat, you need a calorie deficit—eat fewer calories than your TDEE over time. [6]
• To gain weight or muscle, eat more than your TDEE—ideally with resistance training and enough protein. [7]

Because TDEE reflects your “maintenance” needs, it’s a useful baseline to plan how many calories to eat based on your goals. [8]

How to estimate your TDEE & adjust calories for goals

1. Estimate your BMR using a validated formula.
   Most calculators use this method because it’s considered highly accurate for the general population. 

2. Select your activity level.
   Choose based on how much you move or exercise. The activity multiplier adjusts your BMR to estimate TDEE. 
3. Adjust calorie intake based on goal: 
   Weight maintenance → eat ≈ TDEE 
   
   Weight loss → eat less than TDEE. Many sources suggest a ~500 kcal/day deficit, which may yield about 1 lb/week (≈ 0.45 kg) of fat loss. [9]
   
   Muscle gain / weight gain → eat slightly above TDEE (a modest surplus), especially with strength training. [10]

Your calorie needs can shift based on changes in weight, muscle mass, or activity level. [11]

Applying it: weight loss vs muscle gain strategies

• Moderate calorie deficit (~500 kcal/day) supports ~1 lb/week fat loss. [12]
• Combine calorie reduction with moderate aerobic and strength training to preserve muscle. [13]
• Focus on nutrient-dense foods—fruits, veggies, lean protein, whole grains—for satiety and health. [14]
• Avoid extreme low-calorie diets (e.g., <800 kcal/day) that can cause fatigue, nutrient gaps, and slow metabolism. [15]

For muscle gain (or lean mass gain)

• Slight calorie surplus above TDEE helps support lean mass gains without excess fat. [16]
• Pair with strength training and adequate protein to support repair and muscle growth. [17]
• As lean mass increases, your energy needs rise—so recalculating TDEE over time helps. [18]

What to keep in mind — limitations & why results vary 

• TDEE calculations are estimates and can vary based on genetics, hormones, lean body mass (muscle vs. fat), lifestyle, and daily activity. 

• Prolonged calorie deficits (dieting) may lower energy output over time by reducing your BMR,  NEAT, and TEFF (Thermic Effect of Food)—all of which can slow weight loss. 

• “500 cal = 1 lb/week” is a rough rule. Fat loss is non-linear and influenced by water retention and metabolism. [19]

• Long-term success depends on more than calories—nutrition quality, movement, sleep, stress, and health conditions all matter. Your long-term success is more likely the more holistic your approach is. [20]

Summary: how to use this calculator

• Use TDEE (or an estimate) as your maintenance calorie baseline — how many calories you need to stay the same weight. 

• Define your goal:
  Lose fat → eat slightly below TDEE + add activity.
  Gain muscle/lean mass → eat slightly above TDEE + include protein & strength training. 

• Track and adjust regularly:
  If your weight, body composition, or activity level changes, recalculate your TDEE or calorie targets. Focus on quality nutrition and long-term habits — not just numbers. Use expert tools (like the Body Weight Planner) and talk to a healthcare provider, especially if you have health issues, obesity, or are aiming for significant weight change. 

22 Sources

1. TDEE Calculator — What It Is & How It Works (incl. BMR, activity, TEF, NEAT). Calc Bloom
2. TDEE components and how total calories burned are used for weight planning. Calorie deficit calculator
3. What Is Total Daily Energy Expenditure (TDEE)? Very Well Fit
4. What Is TDEE? Very Well Fit
5. Body weight planner. NIDDK
6. Counting calories for weight loss. Medical News Today
7. How Does Calorie Balance Work? Fitness Rec
8. TDEE  reflects your “maintenance”. Forbes
9. Weight loss → eat less than TDEE. NIH News in Health
10. Muscle gain / weight gain . FitnessRec
11. Your calorie needs can shift based on changes in weight, muscle mass, or activity level. Forbes
12. Moderate calorie deficit (~500 kcal/day) supports ~1 lb/week fat loss. NIH News in Health
13. Combine calorie reduction with moderate aerobic and strength training to preserve muscle. NIDDK
14. Focus on nutrient-dense foods—fruits, veggies, lean protein, whole grains—for satiety and health. NIH News in Health
15. Avoid extreme low-calorie diets (e.g., <800 kcal/day) that can cause fatigue, nutrient gaps, and slow metabolism. Medical News Today
16. Slight calorie surplus above TDEE helps support lean mass gains without excess fat. FitnessRec
17. Pair with strength training and adequate protein to support repair and muscle growth. University of New Mexico
18. As lean mass increases, your energy needs rise—so recalculating TDEE over time helps. Lifting Strength
19. Fat loss is non-linear and influenced by water retention and metabolism. National Library of Medicine
20. Long-term success depends on more than calories. NIDDK