Basal Metabolic Rate (BMR) Calculator
What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to perform essential life-sustaining functions while at rest. These functions include breathing, circulation, cell production, nutrient processing, protein synthesis, and the transport of ions. Think of it as the energy your body expends just to keep you alive if you were to do absolutely nothing all day.
Your BMR is influenced by several factors, including your age, gender, body weight, and height. Muscle tissue burns more calories than fat tissue, so individuals with more muscle mass tend to have a higher BMR. As people age, their metabolic rate generally slows down.
How is BMR Calculated?
There are several formulas to estimate BMR. The most common ones are the Harris-Benedict equation (original and revised) and the Mifflin-St Jeor equation. This calculator uses the Mifflin-St Jeor equation, which is generally considered more accurate for most people.
Mifflin-St Jeor Equation:
- 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
The result from this calculator provides an estimate of your BMR in kilocalories (kcal) per day. This value is crucial for understanding your daily energy needs and can be a starting point for weight management plans, as it forms the baseline for your total daily energy expenditure.
Example Calculation
Let's calculate the BMR for a 35-year-old male who weighs 80 kg and is 180 cm tall.
- Gender: Male
- Weight: 80 kg
- Height: 180 cm
- Age: 35 years
Using the Mifflin-St Jeor equation for men: BMR = (10 × 80) + (6.25 × 180) – (5 × 35) + 5 BMR = 800 + 1125 – 175 + 5 BMR = 1755 kcal/day
This means the individual needs approximately 1755 calories per day to maintain basic bodily functions at rest.