BMR Calculator

Calculate your Basal Metabolic Rate (BMR) to understand how many calories your body burns at rest and determine your daily calorie needs based on activity level.

Examples

• 25-year-old male, 75kg, 180cm = ~1,800 BMR
• 30-year-old female, 60kg, 165cm = ~1,400 BMR
• Sedentary lifestyle: BMR × 1.2 for daily needs

How to Use the BMR Calculator

Using our BMR calculator is straightforward and provides comprehensive results for your metabolism:

  1. Select your gender (male or female)
  2. Choose your preferred unit system (Metric or Imperial)
  3. Enter your age in years
  4. Enter your weight in kilograms (kg) or pounds (lbs)
  5. Enter your height in centimeters (cm) or feet and inches
  6. Click "Calculate BMR" to get your results

The calculator provides your BMR using the Mifflin-St Jeor equation (most accurate) and Harris-Benedict equation for comparison, plus daily calorie needs for different activity levels.

Understanding BMR (Basal Metabolic Rate)

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions while at complete rest. These functions include breathing, circulation, cell production, nutrient processing, protein synthesis, and brain function.

BMR typically accounts for 60-75% of total daily energy expenditure in sedentary individuals. Understanding your BMR is crucial for weight management, nutrition planning, and understanding your body's energy needs.

Factors Affecting BMR

  • Age: BMR decreases with age due to loss of muscle mass
  • Gender: Men typically have higher BMR due to more muscle mass
  • Weight: Heavier individuals have higher BMR
  • Height: Taller individuals have higher BMR
  • Body composition: More muscle mass increases BMR
  • Genetics: Some people naturally have faster or slower metabolism

Formula & Calculation Methods

Our calculator uses two well-established formulas:

Mifflin-St Jeor Equation (Recommended)

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) - 161

Harris-Benedict Equation (Traditional)

Men: BMR = 88.362 + (13.397 × weight(kg)) + (4.799 × height(cm)) - (5.677 × age(years))
Women: BMR = 447.593 + (9.247 × weight(kg)) + (3.098 × height(cm)) - (4.330 × age(years))

The Mifflin-St Jeor equation is considered more accurate for most people, while the Harris-Benedict equation is the traditional method. Both are provided for comparison.

Activity Level Multipliers

To calculate daily calorie needs, multiply your BMR by your activity level factor:

  • Sedentary (1.2): Little or no exercise
  • Lightly Active (1.375): Light exercise/sports 1-3 days/week
  • Moderately Active (1.55): Moderate exercise/sports 3-5 days/week
  • Very Active (1.725): Hard exercise/sports 6-7 days/week
  • Extra Active (1.9): Very hard exercise/sports & physical job

Frequently Asked Questions

What's the difference between BMR and metabolism?

BMR is specifically the calories needed at complete rest, while metabolism includes all energy expenditure including digestion, physical activity, and thermal regulation. BMR is the largest component of total metabolism.

How accurate are BMR calculations?

BMR calculations are estimates with accuracy of ±10-15%. Individual variations in genetics, body composition, and health conditions can affect actual BMR. For precise measurements, indirect calorimetry testing is needed.

Can I increase my BMR?

Yes! Building muscle mass through strength training is the most effective way to increase BMR. Muscle tissue burns more calories at rest than fat tissue. Regular exercise, adequate sleep, and proper nutrition also support healthy metabolism.

Why do men have higher BMR than women?

Men typically have higher BMR due to greater muscle mass, larger body size, and hormonal differences. Testosterone promotes muscle development, and muscle tissue has higher metabolic activity than fat tissue.

Tips & Best Practices

  • Use BMR as a baseline for calorie intake planning
  • Choose activity level honestly for accurate daily calorie needs
  • Remember that BMR decreases with age - adjust accordingly
  • Build muscle through strength training to increase BMR
  • Don't eat below BMR for extended periods without medical supervision
  • Consider body composition, not just weight, for metabolism
  • Track changes over time rather than relying on single calculations
  • Consult healthcare providers for personalized nutrition advice