How Does the Calorie Calculator Work?
Your Total Daily Energy Expenditure (TDEE) represents the total aggregate number of calories your body burns across a 24-hour cycle. TDEE comprises two foundational pillars:
- Basal Metabolic Rate (BMR): The baseline energy consumed to sustain vital biological functions (breathing, cellular repair, cardiac circulation, core temperature regulation) in a state of complete rest.
- Physical Activity Level: Energy expended through daily movement, work tasks, and structured physical exercise.
Formula & Mathematical Methodology
We compute BMR using the scientifically validated Mifflin-St Jeor Equation:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
To determine total daily calorie requirements (TDEE), BMR is multiplied by an activity factor:
- Sedentary (desk job, minimal exercise):
BMR × 1.2 - Lightly active (light exercise 1–3 days/week):
BMR × 1.375 - Moderately active (moderate exercise 3–5 days/week):
BMR × 1.55 - Very active (hard exercise 6–7 days/week):
BMR × 1.725
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Step-by-Step Practical Calculation Example
A 30-year-old male weighing 75 kg and measuring 180 cm with moderate activity:
- BMR: (10 × 75) + (6.25 × 180) - (5 × 30) + 5 = 750 + 1125 - 150 + 5 = 1,730 kcal/day
- TDEE (Moderate): 1,730 × 1.55 = 2,682 kcal/day
- Weight Loss Deficit (-500 kcal): 2,182 kcal/day
- Weight Gain Surplus (+500 kcal): 3,182 kcal/day