BMR Calculator - Basal Metabolic Rate

Calculate your Basal Metabolic Rate (BMR) for free. Discover how many calories your body burns at rest using the Mifflin-St Jeor and Harris-Benedict formulas.

Important Medical Disclaimer

This calculator is an educational and clinical decision support tool. Results DO NOT replace professional medical evaluation, laboratory tests, or clinical judgment. Always consult a qualified healthcare professional for diagnosis, treatment, and clinical decisions. Calculations are based on scientifically validated formulas but may not be applicable to all patients.

Calculate BMR

What is Basal Metabolic Rate (BMR)?

Basal Metabolic Rate (BMR), also called Basal Metabolism, represents the minimum amount of energy (calories) your body needs to maintain vital functions at absolute rest. This includes breathing, blood circulation, cell production, nutrient processing, and body temperature maintenance. BMR accounts for about 60-75% of Total Energy Expenditure (TEE) daily.

Calculation Formulas

Mifflin-St Jeor (1990) - Recommended

Considered more accurate and updated. Developed in 1990 based on more recent studies.

Men: BMR = (10 × weight) + (6.25 × height) - (5 × age) + 5

Women: BMR = (10 × weight) + (6.25 × height) - (5 × age) - 161

Harris-Benedict (1919) - Classic

Original formula created in 1919. Still widely used, but may overestimate caloric expenditure.

Men: BMR = 88.362 + (13.397 × weight) + (4.799 × height) - (5.677 × age)

Women: BMR = 447.593 + (9.247 × weight) + (3.098 × height) - (4.330 × age)

How to Use the BMR Calculator

To calculate your BMR, enter your weight in kilograms, height in centimeters, and age in years. Before calculating BMR, you can check if your weight is appropriate using our BMI calculator. Select your biological sex and choose the desired formula (we recommend Mifflin-St Jeor for greater accuracy). The result will show how many calories your body burns per day at rest. To know your total expenditure including your daily activities and exercise, use our Total Energy Expenditure (TEE) calculator that multiplies BMR by your physical activity factor.

Limitations and Considerations

BMR is an estimate based on population averages. Factors such as muscle mass, genetics, hormones, ambient temperature, stress, and health status can affect actual metabolism. Athletes with high muscle mass tend to have higher BMR. People on prolonged restrictive diets may have reduced BMR (metabolic adaptation). For a more accurate assessment of calorie expenditure during exercise, use our calorie burn calculator. If you are overweight, consider evaluating your BMI to better understand your body composition. Always consult a nutritionist for personalized guidance on your caloric needs.

Frequently Asked Questions about BMR

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the caloric expenditure at absolute rest. TDEE (Total Daily Energy Expenditure) is BMR multiplied by the level of physical activity, representing the total daily expenditure including exercises and daily activities.

How can I increase my BMR?

The best way to increase BMR is through muscle mass gain with strength training (weight lifting). Muscles burn more calories at rest than fat. Use our calorie burn calculator to see how much you burn during workouts. It also helps to: have regular meals, sleep well (7-9h), avoid very restrictive diets, and stay hydrated.

Why does BMR decrease with age?

With aging, muscle mass loss (sarcopenia) and reduction in hormonal activity naturally occur, which decreases basal metabolism. After 30 years, BMR reduces about 2-3% per decade. Strength exercises help minimize this reduction.

Is BMR different for men and women?

Yes. Men generally have higher BMR because they tend to have more muscle mass and less body fat than women. The formulas consider these biological differences in calculations.

Can I use BMR to lose weight?

Yes. To lose weight healthily, consume calories below your TDEE (Total Daily Energy Expenditure), but never less than your BMR. Very large deficits can slow metabolism. A deficit of 300-500 kcal/day is recommended for gradual and sustainable loss. You can also set a goal using our ideal weight calculator.

Scientific References

1. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-7.
2. Harris JA, Benedict FG. A Biometric Study of Human Basal Metabolism. Proc Natl Acad Sci U S A. 1918;4(12):370-3.
3. World Health Organization. Human energy requirements: report of a Joint FAO/WHO/UNU Expert Consultation. Rome: FAO, 2001.
4. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press, 2005.