❤ Metabolism Helpers

BMI & Calories

Evaluate Body Mass Index, Basal Metabolic Rate, TDEE, and daily macro Targets.

Physical Metrics

Standard Benchmarks

Normal Profile
175 cm, 70 kg (BMI: 22.9)
Obese Profile
180 cm, 100 kg (BMI: 30.9)
Active Male TDEE
178 cm, 80 kg, Age 30, Moderate
Lightly Active Female
165 cm, 55 kg, Age 28, Light

Understanding Metabolism & Energy Balance

Maintaining health and managing body mass depends on the laws of thermodynamics — specifically the relation between energy intake (calories eaten) and energy expenditure (calories burned).

What is Body Mass Index (BMI)?

The Body Mass Index is a simple numerical metric that classifies an individual's weight status relative to their height. It is calculated by dividing weight in kilograms by height in meters squared:

BMI = Weight (kg) / Height (m)^2

The World Health Organization (WHO) classifies BMI values as:

  • Underweight: BMI less than 18.5
  • Normal Weight: BMI between 18.5 and 24.9
  • Overweight: BMI between 25.0 and 29.9
  • Obese: BMI of 30.0 or greater

Basal Metabolic Rate (BMR) vs. TDEE

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to perform vital life functions, such as breathing, circulating blood, and cell production.

Your Total Daily Energy Expenditure (TDEE) is the total number of calories burned in a day, which factors in your activity level. We calculate BMR using the highly validated Mifflin-St Jeor Equation:

Male: BMR = 10 × Weight(kg) + 6.25 × Height(cm) − 5 × Age(y) + 5
Female: BMR = 10 × Weight(kg) + 6.25 × Height(cm) − 5 × Age(y) − 161

TDEE is then calculated by multiplying BMR by an activity multiplier (from 1.2 for sedentary to 1.9 for extra active).

Frequently Asked Questions

Is BMI an accurate measure of body fat? +
BMI is a general screening tool, but it has limitations. It does not distinguish between muscle tissue and fat tissue. For example, athletes or bodybuilders with high muscle mass can have a BMI in the "overweight" or "obese" category despite having very low body fat.
How do you calculate calorie needs for weight loss? +
To lose weight, you must create an energy deficit by consuming fewer calories than your TDEE. A safe, sustainable target is a deficit of 500 kcal per day, which results in approximately 0.5 kg (1 lb) of weight loss per week.
What are macronutrients and how are they split? +
Macronutrients are the nutrients your body needs in large quantities: Carbohydrates (4 kcal/g), Proteins (4 kcal/g), and Fats (9 kcal/g). A standard healthy macro distribution is 50% Carbs, 25% Protein, and 25% Fats.