BMR Calculator (Harris-Benedict Equation)
Calculate your BMR using the Harris-Benedict equation and get TDEE adjusted by activity level. Free online health calculator for weight management and daily calorie planning.
About This Calculator
The Harris-Benedict Equation is one of the most widely used formulas for calculating your Basal Metabolic Rate (BMR) — the number of calories your body needs at complete rest to maintain essential functions like breathing, circulation, and cell production. First published in 1918 by James Arthur Harris and Francis Gano Benedict, this scientifically validated equation remains a cornerstone of nutritional science and weight management.
Our calculator uses the revised Harris-Benedict equations: for men, BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) − (6.75 × age); for women, BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) − (4.676 × age). After calculating your BMR, it multiplies by your selected activity factor to estimate your Total Daily Energy Expenditure (TDEE) — the total calories you burn daily including physical activity.
How to use your results
Your TDEE is your maintenance calorie level. To maintain your current weight, consume this many calories daily. To lose weight, create a deficit of 300–500 calories below your TDEE. To gain muscle, add 200–300 calories above TDEE combined with strength training. Always consult a healthcare professional before starting any diet or exercise program, especially if you have underlying health conditions.
Regional Notes
India: The Harris-Benedict equation is used by nutritionists and fitness professionals across India. Default weight is 70 kg and height is 170 cm, reflecting average adult Indian body measurements. Calorie needs should be adjusted for regional dietary patterns and activity levels common in urban and rural settings.
US: Common in clinical and fitness settings. Defaults use 154 lb (70 kg) weight and 5'7" (170 cm) height. The CDC recommends adults get 150+ minutes of moderate activity weekly, which corresponds to the Lightly Active or Moderately Active activity factor.
UK: Widely used by the NHS and dietitians for weight management guidance. Defaults use 75 kg weight and 175 cm height reflecting UK averages. The NHS recommends a balanced calorie deficit of 600 kcal/day for sustainable weight loss of 0.5–1 kg per week.
Frequently Asked Questions
What is the Harris-Benedict equation?
The Harris-Benedict equation is a formula that calculates your Basal Metabolic Rate (BMR) based on your age, sex, weight, and height. It was first published in 1918 by James Harris and Francis Benedict and remains widely used for estimating daily calorie needs. There are separate formulas for men and women using weight in kilograms, height in centimeters, and age in years.
How do I calculate my BMR using the Harris-Benedict equation?
For men: BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) - (6.75 × age). For women: BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) - (4.676 × age). Simply enter your weight, height, age, and select your gender, then click calculate to get your BMR instantly.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the calories your body needs at complete rest for basic functions like breathing and circulation. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor that accounts for your daily physical activity level. TDEE represents your total daily calorie needs including exercise, work, and daily movement.
How do I use BMR for weight loss?
To lose weight, eat fewer calories than your TDEE. A deficit of 500 calories per day typically leads to about 0.5 kg (1 lb) of weight loss per week. Never eat below your BMR as your body needs those calories for essential functions. Combine a modest calorie deficit with regular exercise for sustainable weight loss.
What activity factor should I use?
Sedentary (1.2): little or no exercise. 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): very hard exercise plus physical job. Choose the option closest to your typical activity level.
Is the Harris-Benedict equation accurate?
The Harris-Benedict equation is considered reasonably accurate for estimating BMR in the general population, with an accuracy of about ±10% for most individuals. It may overestimate BMR in obese individuals and underestimate in very muscular people. The Mifflin-St Jeor equation is sometimes preferred as it was developed more recently (1990) and may be slightly more accurate.
What is a normal BMR?
The average BMR is about 1,409 calories per day for women and about 1,696 calories per day for men. However, your individual BMR depends on your age, weight, height, sex, and body composition. Younger people and those with more muscle mass typically have higher BMRs.
How can I increase my BMR naturally?
To increase your BMR naturally: build muscle through resistance training as muscle burns more calories than fat at rest; eat enough protein which has a higher thermic effect; stay active throughout the day with NEAT (non-exercise activity thermogenesis); get adequate sleep as poor sleep can lower metabolic rate; and eat regular meals to avoid metabolic slowdown.