Basal Metabolic Rate (BMR) Calculator
Your Basal Metabolic Rate:
Understanding Your Basal Metabolic Rate (BMR)
Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, life-sustaining functions while at rest. Think of it as the energy your body expends to keep your heart beating, lungs breathing, brain functioning, and cells repairing themselves. This is the minimum energy required to keep you alive if you were to do absolutely nothing.
Your BMR is influenced by several factors, including your gender, weight, height, and age. Generally, men tend to have a higher BMR than women due to differences in muscle mass and body composition. As you age, your BMR typically decreases because muscle mass can decline. Your body size also plays a role; a larger body requires more energy to maintain.
The Mifflin-St Jeor Equation
The most commonly used and widely accepted formula for calculating BMR is the Mifflin-St Jeor equation. It is considered more accurate than older formulas like the Harris-Benedict equation. The formulas are as follows:
- 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 constant '+ 5' for men and '- 161' for women accounts for general physiological differences.
How to Use the Calculator
Our BMR calculator simplifies this process for you. Simply input your gender, weight in kilograms, height in centimeters, and age in years. The calculator will then apply the Mifflin-St Jeor equation to provide an estimate of your daily calorie needs at rest.
Example Calculation
Let's consider an example: Sarah is a 30-year-old woman who weighs 65 kg and is 165 cm tall.
Using the Mifflin-St Jeor equation for women:
BMR = (10 × 65) + (6.25 × 165) – (5 × 30) – 161
BMR = 650 + 1031.25 – 150 – 161
BMR = 1370.25 kcal/day
So, Sarah's BMR is approximately 1370.25 calories per day. This is the baseline energy she needs just to survive.
Beyond BMR: Total Daily Energy Expenditure (TDEE)
It's important to remember that BMR is just one part of your total daily energy expenditure (TDEE). TDEE also includes the calories you burn through physical activity, the thermic effect of food (digesting food), and other non-exercise activity thermogenesis (NEAT). To determine your total daily calorie needs for weight management or maintenance, you would multiply your BMR by an activity factor.
Understanding your BMR is a foundational step in managing your nutrition and understanding your body's energy requirements.