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Harris-Benedict BMR Calculator

Calculate your BMR using the scientifically validated Harris-Benedict equation. Choose between the original (1919) or revised (1984) formula for personalized calorie targets.

Enter age between 15-100 years
Enter weight between 30-300
Enter height between 100-250 cm
How often do you exercise?
Revised formula recommended for modern populations

Your Results

Enter your details and calculate to see results.

Quick Tips
  • Be honest about activity level - Most people overestimate
  • Never eat below BMR long-term - It slows metabolism
  • Track your weight weekly and adjust calories accordingly
  • Use the Revised (1984) formula for better accuracy
  • Recalculate every 5kg weight loss or gain
Important Disclaimer
This calculator estimates BMR using Harris-Benedict equations. Not personalized medical advice. Consult healthcare professionals for medical conditions.
Learn More

Harris-Benedict Formulas:

  • Revised (1984): More accurate for modern populations
  • Original (1919): Historical/research purposes

Healthline: BMR & Calorie Needs

Mayo Clinic: Daily Calorie Needs

Related Calculators

Key Features

Dual Formula Support

Choose between the Original (1919) and Revised (1984) Harris-Benedict equations for maximum flexibility and accuracy.

Complete TDEE Calculation

Get your Total Daily Energy Expenditure with 5 activity levels from sedentary to extra active for precise calorie targeting.

Personalized Calorie Goals

Receive custom daily calorie targets for weight loss (moderate & aggressive), maintenance, and muscle gain.

Macro Breakdown

Get detailed macronutrient recommendations (protein, carbs, fats) tailored to your activity level and goals.

How to Use

  1. Select your gender - Male or Female (biological sex affects BMR calculation)
  2. Enter your age - Between 15-100 years (metabolism decreases with age)
  3. Input your weight - In kilograms or pounds (higher weight = higher BMR)
  4. Input your height - In centimeters or inches (taller people burn more calories)
  5. Choose activity level - Be honest! Overestimating leads to weight gain
  6. Select formula version - Use Revised (1984) for better accuracy
  7. Click Calculate - View your BMR, TDEE, calorie goals, and macro recommendations
  8. Use results to plan diet - Eat below TDEE to lose weight, above to gain muscle

Understanding Results

BMR is the number of calories your body burns at complete rest - just to keep you alive. This includes:

  • Breathing and circulation
  • Cell production and repair
  • Nutrient processing
  • Brain and nervous system function

Important: BMR accounts for 60-75% of your total daily calorie burn. You should never eat below your BMR for extended periods.

TDEE is your total calorie burn including all activities:

  • BMR (basal metabolic rate)
  • NEAT (Non-Exercise Activity Thermogenesis) - daily movement
  • Exercise and planned workouts
  • TEF (Thermic Effect of Food) - calories burned digesting

Formula: TDEE = BMR × Activity Multiplier

  • Aggressive Loss (-750 cal): Lose ~0.75 kg per week. Only recommended if you have 15+ kg to lose.
  • Moderate Loss (-500 cal): Lose ~0.5 kg per week. Sustainable for most people.
  • Maintenance (TDEE): Maintain current weight. Use when taking diet breaks.
  • Weight Gain (+500 cal): Gain ~0.5 kg per week. Combine with strength training for muscle growth.

Protein: 1.2-1.6g per kg body weight. Builds muscle, repairs tissue, increases satiety.

Fats: ~25% of total calories. Essential for hormones, nutrient absorption, brain function.

Carbohydrates: Remaining calories. Primary energy source, especially for exercise.

Calculation Formula

Revised Harris-Benedict Equation (1984) - Recommended
For Men:
BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age)
For Women:
BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age)
Original Harris-Benedict Equation (1919)
For Men:
BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) - (6.755 × age)
For Women:
BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) - (4.676 × age)
Activity Multipliers for TDEE
  • Sedentary (×1.2): Little to no exercise, desk job
  • Lightly Active (×1.375): Light exercise 1-3 days/week
  • Moderately Active (×1.55): Moderate exercise 3-5 days/week
  • Very Active (×1.725): Hard exercise 6-7 days/week
  • Extra Active (×1.9): Physical job + hard daily exercise

Real World Examples

Example 1: Office Worker
Male, 30 years old
  • Weight: 80 kg
  • Height: 178 cm
  • Activity: Sedentary (desk job)
BMR:
1,794 cal/day
TDEE:
2,153 cal/day
Weight Loss:
1,653 cal/day
Example 2: Fitness Enthusiast
Female, 25 years old
  • Weight: 60 kg
  • Height: 165 cm
  • Activity: Very Active (gym 6x/week)
BMR:
1,383 cal/day
TDEE:
2,386 cal/day
Muscle Gain:
2,886 cal/day

Common Mistakes to Avoid

Overestimating Activity Level

Most people are sedentary or lightly active. Unless you have a physical job or exercise intensely 6-7 days/week, choose a lower activity level.

Eating Below BMR

Never consistently eat below your BMR. This can slow metabolism, cause muscle loss, and trigger hormonal imbalances. Always use TDEE for diet planning.

Aggressive Deficit Too Long

A 750-calorie deficit is only for those with significant weight to lose. Most should use 500 calories or less and take regular diet breaks.

Ignoring Individual Variation

BMR calculators provide estimates. Monitor your actual weight change over 2-4 weeks and adjust calories by 100-200 if needed.

Not Tracking Food Accurately

Use a food scale and track everything. Estimating portions can lead to 300-500 calorie errors daily.

Frequently Asked Questions

The Harris-Benedict equation is a scientifically validated formula for calculating Basal Metabolic Rate (BMR) - the number of calories your body burns at rest. First published in 1919 by J. Arthur Harris and Francis Benedict, it was revised in 1984 by Roza and Shizgal for improved accuracy with modern populations.

Use the Revised Harris-Benedict (1984) for better accuracy. The revised version updated the coefficients based on more recent research and modern body composition data. Both formulas give similar results (within 5%), but the revised version is generally more accurate for contemporary populations.

The Harris-Benedict equation has an accuracy of ±10-15% for most people. Individual factors like muscle mass, genetics, medications, and metabolic conditions can affect actual BMR. Use the calculator as a starting point, then adjust based on real-world weight changes over 2-4 weeks.

Always base your diet on TDEE, not BMR. BMR is what you burn at complete rest - you burn significantly more with daily activities. To lose weight, eat 300-750 calories below your TDEE. To gain muscle, eat 300-500 above TDEE. Never consistently eat below your BMR.

Men typically have higher BMR due to greater muscle mass and testosterone levels. Muscle tissue burns more calories at rest than fat tissue. On average, men have 15-20% more muscle mass than women of similar size, resulting in 5-10% higher BMR.

Recalculate your BMR and TDEE every 5-10 kg of weight change or every 2-3 months. As you lose weight, your calorie needs decrease. Failing to adjust can lead to weight loss plateaus. Also recalculate if your activity level changes significantly.

Yes, but the Harris-Benedict equation may be less accurate at extreme body weights. For obesity (BMI > 30), the Mifflin-St Jeor equation is sometimes more accurate. For underweight individuals or athletes with very low body fat, consult a registered dietitian for personalized recommendations.

Yes, BMR decreases approximately 1-2% per decade after age 20 due to muscle loss (sarcopenia) and hormonal changes. The Harris-Benedict equation accounts for this with the age coefficient. Strength training can help maintain muscle mass and minimize BMR decline.

Additional Resources

Related Calculators
Further Reading
  • Original Harris-Benedict study (1919)
  • Roza AM, Shizgal HM. Revised equation (1984)
  • WHO/FAO guidelines on energy requirements
  • American Dietetic Association recommendations
Medical Disclaimer

This calculator provides estimates for educational purposes only. Results are not medical advice. Individual metabolic rates vary based on genetics, muscle mass, medications, and health conditions. Consult a registered dietitian or healthcare provider before starting any diet or weight loss program, especially if you have medical conditions, take medications, or are pregnant/nursing.