Metabolic Rate Calculator Body Fat

Metabolic Rate Calculator

This calculator estimates your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).

Understanding Your Metabolic Rate

Your metabolic rate refers to the total number of calories your body burns in a 24-hour period. It's a crucial factor in understanding weight management, energy levels, and overall health. There are two primary components to your metabolic rate: your Basal Metabolic Rate (BMR) and your Total Daily Energy Expenditure (TDEE).

Basal Metabolic Rate (BMR)

Your BMR is the minimum number of calories your body needs to perform its essential, life-sustaining functions while at rest. These functions include breathing, circulation, cell production, nutrient processing, and protein synthesis. It's the energy your body would burn if you were to spend the entire day doing absolutely nothing but sleeping.

The most common and widely accepted formula for calculating BMR is the Mifflin-St Jeor equation, which is used in this calculator:

• For men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
• For women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Total Daily Energy Expenditure (TDEE)

Your TDEE takes your BMR and adds the calories you burn through physical activity and the thermic effect of food (the energy used to digest, absorb, and metabolize nutrients). This calculator estimates your TDEE by multiplying your BMR by an activity factor that represents your lifestyle.

The activity factors are commonly used multipliers:

• Sedentary: little to no exercise (BMR × 1.2)
• Lightly active: light exercise/sports 1-3 days/week (BMR × 1.375)
• Moderately active: moderate exercise/sports 3-5 days/week (BMR × 1.55)
• Very active: hard exercise/sports 6-7 days a week (BMR × 1.725)
• Extra active: very hard exercise/sports & physical job (BMR × 1.9)

Why is This Important?

Understanding your metabolic rate helps you make informed decisions about your diet and exercise. If your goal is to lose weight, you generally need to consume fewer calories than your TDEE. If your goal is to gain weight or muscle, you'll likely need to consume more calories than your TDEE. For weight maintenance, your calorie intake should be close to your TDEE.

Example: Let's consider a 35-year-old male, weighing 80 kg, who is 180 cm tall and moderately active (exercises 3-5 days a week). His BMR would be calculated as: (10 × 80) + (6.25 × 180) – (5 × 35) + 5 = 800 + 1125 – 175 + 5 = 1755 kcal/day. His TDEE would then be: 1755 kcal/day × 1.55 (moderately active factor) = 2720.25 kcal/day. This means he needs approximately 2720 calories per day to maintain his current weight.