BMR Calculator

Calculate your Basal Metabolic Rate with validated scientific formulas

Personal Information

Required for Katch-McArdle and Cunningham formulas

BMR Results

Harris-Benedict (1984) ±10-15% accuracy
1,750 kcal/day
Classic formula - General population
Mifflin-St Jeor (1990) ±5-10% accuracy
1,675 kcal/day
Recommended - Most accurate for modern population
Katch-McArdle ±3-5% accuracy
Enter body fat %
Athletes - Requires body fat percentage
Cunningham ±2-4% accuracy
Enter body fat %
Elite athletes - Highest accuracy for very active

Daily Calorie Needs (TDEE)

Sedentary (office job): 2,010 kcal
Light activity (1-3 days/week): 2,303 kcal
Moderate activity (3-5 days/week): 2,596 kcal
High activity (6-7 days/week): 2,889 kcal
Extreme activity (2x/day): 3,183 kcal

When to Use BMR Calculator

Weight Loss Planning

Calculate your baseline calorie needs to create an effective calorie deficit for sustainable weight loss without metabolic damage.

Athletic Performance

Use athlete-specific formulas to optimize nutrition timing and calorie intake for training, competition, and recovery phases.

Health Monitoring

Track metabolic changes over time due to aging, lifestyle changes, or medical conditions affecting metabolism.

Nutrition Counseling

Professional dietitians and nutritionists use BMR calculations as the foundation for personalized meal planning and dietary recommendations.

Medical Research

Healthcare professionals use BMR data for metabolic studies, treatment planning, and assessing the effectiveness of interventions.

Fitness Goal Setting

Establish realistic calorie targets for bulking, cutting, or maintenance phases in bodybuilding and fitness programs.

Frequently Asked Questions

What is BMR (Basal Metabolic Rate)?

BMR is the minimum number of calories your body needs to maintain basic physiological functions at rest, including breathing, circulation, cell production, nutrient processing, and brain function. It represents 60-75% of your total daily energy expenditure and forms the foundation for calculating your daily calorie needs.

Which BMR formula is most accurate?

The Mifflin-St Jeor equation (1990) is considered most accurate for the general population with ±5-10% accuracy. For athletes and very active individuals, the Katch-McArdle formula (±3-5% accuracy) or Cunningham formula (±2-4% accuracy) are more precise as they account for lean body mass and body composition.

How do I use BMR to calculate daily calorie needs?

Multiply your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE): Sedentary lifestyle (×1.2), Light activity 1-3 days/week (×1.375), Moderate activity 3-5 days/week (×1.55), High activity 6-7 days/week (×1.725), or Extreme activity twice daily (×1.9).

Is this BMR calculator free to use?

Yes, our BMR calculator is completely free with no registration, subscription fees, or usage limitations. All calculations are performed locally in your browser using JavaScript, ensuring complete privacy protection and instant results without server dependencies.

What's the difference between BMR formulas?

Harris-Benedict (1984) is the classic formula widely used in clinical settings, Mifflin-St Jeor (1990) is more accurate for modern populations, Katch-McArdle uses lean body mass making it ideal for athletes, and Cunningham is optimized for very active individuals and bodybuilders with known body composition.

Do I need body fat percentage for BMR calculation?

Body fat percentage is only required for the Katch-McArdle and Cunningham formulas, which calculate BMR based on lean body mass. The Harris-Benedict and Mifflin-St Jeor formulas only need age, gender, height, and weight for accurate calculation.

How accurate are BMR calculations?

BMR accuracy varies by formula: Harris-Benedict (±10-15%), Mifflin-St Jeor (±5-10%), Katch-McArdle (±3-5%), and Cunningham (±2-4%). Individual variations in genetics, muscle mass, metabolic efficiency, and health conditions can affect actual BMR, so these are estimates for planning purposes.

Can I download or save my BMR results?

Yes, you can easily copy your BMR results to the clipboard or download them as a comprehensive report including all formula comparisons, TDEE calculations, and recommendations. The download includes detailed explanations of each formula and their appropriate use cases.

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