BMR Calculator
Calculate your Basal Metabolic Rate using three proven scientific formulas. Find out how many calories your body burns at complete rest — the foundation for any nutrition plan.
Frequently Asked Questions
What is BMR?
BMR stands for Basal Metabolic Rate. It is the number of calories your body burns at complete rest — just to keep your organs functioning, blood circulating, and cells alive. Your BMR typically accounts for 60-75% of your total daily calorie burn, making it the single largest component of your energy expenditure.
What's the difference between BMR and TDEE?
BMR measures only the calories burned at complete rest — the energy needed for basic life-sustaining functions like breathing and circulation. TDEE (Total Daily Energy Expenditure) is your BMR plus all additional calories burned through physical activity, exercise, and the thermic effect of food (digestion). Your TDEE is always higher than your BMR.
How can I increase my BMR?
The most effective way to increase your BMR is to build muscle mass through resistance training, since muscle tissue burns more calories at rest than fat tissue. Other strategies include staying physically active throughout the day, getting adequate sleep (7-9 hours), eating enough protein, and avoiding crash diets that can slow your metabolism.
Does BMR decrease with age?
Yes, BMR typically decreases by about 1-2% per decade after age 20. This decline is primarily due to the gradual loss of lean muscle mass (sarcopenia) that occurs with aging. Regular strength training and adequate protein intake can help slow this decline by preserving and building muscle tissue.
Understanding BMR and the Three Formulas
Your Basal Metabolic Rate is the number of calories your body needs at complete rest — just to keep your heart beating, lungs breathing, and cells functioning. It typically accounts for 60-75% of total daily calorie burn and is the starting point for any calorie or macro calculation.
Mifflin-St Jeor (Recommended)
Male: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5
Female: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161
Published in 1990, the Mifflin-St Jeor equation is recommended by the Academy of Nutrition and Dietetics as the most accurate predictive equation for estimating BMR in healthy, non-obese adults. It is accurate to within about 10% for most people.
Harris-Benedict (Revised)
Male: BMR = 13.397 x weight(kg) + 4.799 x height(cm) - 5.677 x age + 88.362
Female: BMR = 9.247 x weight(kg) + 3.098 x height(cm) - 4.330 x age + 447.593
Originally published in 1919 and revised in 1984 by Roza and Shizgal, the Harris-Benedict equation was the gold standard for decades. It tends to slightly overestimate BMR compared to Mifflin-St Jeor, especially in overweight individuals, but remains widely used in clinical settings.
Katch-McArdle
Both genders: BMR = 370 + 21.6 x lean body mass(kg)
The Katch-McArdle formula is unique because it uses lean body mass instead of total weight, making it gender-neutral. This makes it the most accurate formula for lean or muscular individuals who know their body fat percentage. If you carry significantly more or less muscle than average, this formula will give you the most reliable estimate.
Which formula should you use?
For most people, Mifflin-St Jeor is the best starting point. If you know your body fat percentage and have above- or below-average muscle mass, the Katch-McArdle formula may be more accurate for you. The Harris-Benedict equation is included as a reference — if all three formulas give you similar numbers, you can be more confident in the estimate.
This calculator provides estimates based on averages. Actual calorie needs vary based on metabolism, body composition, genetics, and other individual factors. Consult a healthcare provider before making significant changes to your diet.