Harris-Benedict Calculator

The Harris-Benedict equation is a formula that estimates your Basal Metabolic Rate (BMR) - the amount of energy your body needs while at complete rest to maintain vital functions such as breathing, circulation, and cell production.

Originally developed in 1919 by James Arthur Harris and Francis Gano Benedict, the equation was later revised in 1984 to improve its accuracy. The Harris-Benedict equation is one of the most widely used methods to estimate BMR and serves as the foundation for calculating total daily energy expenditure.

To calculate your BMR using the Harris-Benedict equation:

1. Select your gender (male or female)
2. Enter your age in years
3. Enter your weight (in kg or lb)
4. Enter your height (in cm or inches)
5. Click the "Calculate" button

The calculator will display your BMR in calories per day, representing the minimum energy your body needs at complete rest.

The revised Harris-Benedict equations (1984) are:

For men:

BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)

For women:

BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)

The original 1919 equations were:

For men:

BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) - (6.755 × age in years)

For women:

BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) - (4.676 × age in years)

Our calculator uses the revised 1984 equations for greater accuracy.

The Harris-Benedict equation has several practical applications:

• Weight management: Calculating your BMR helps determine calorie needs for weight maintenance, loss, or gain.
• Nutritional planning: Healthcare professionals use BMR to develop personalized nutrition plans.
• Fitness programming: Trainers use BMR as a baseline to design appropriate exercise regimens.
• Medical settings: BMR helps determine nutritional requirements for patients in clinical settings.

To calculate your total daily energy expenditure (TDEE), multiply your BMR by an activity factor:

• Sedentary (little or no exercise): BMR × 1.2
• Lightly active (light exercise 1-3 days/week): BMR × 1.375
• Moderately active (moderate exercise 3-5 days/week): BMR × 1.55
• Very active (hard exercise 6-7 days/week): BMR × 1.725
• Extremely active (very hard exercise, physical job or training twice a day): BMR × 1.9

While the Harris-Benedict equation is widely used, it has some limitations:

• Body composition: The equation doesn't account for differences in body composition. People with higher muscle mass may have a higher BMR than predicted.
• Age range: The equation may be less accurate for very young or elderly individuals.
• Extreme body types: The equation may be less accurate for those who are extremely lean or obese.
• Health conditions: Certain medical conditions (thyroid disorders, fever, etc.) can significantly affect BMR.
• Pregnancy and lactation: The equation doesn't account for the increased energy needs during pregnancy or breastfeeding.

For some populations, other equations like the Mifflin-St Jeor or Katch-McArdle formulas may provide more accurate estimates.