Basal Metabolic Rate Calculator
Calculate your basal metabolic rate (BMR) and daily calorie needs with multiple formulas.
Medical Disclaimer
The health and fitness tools provided on this website are for informational and educational purposes only. The information contained herein is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The results provided by these tools are estimates based on general formulas and may not apply to your specific situation. If you think you may have a medical emergency, immediately call your doctor or dial emergency services.
About This BMR Calculator
This BMR calculator estimates your basal metabolic rate - the minimum number of calories your body needs at rest to maintain vital functions.
Our calculator uses three scientifically validated formulas for BMR calculation:
1. Mifflin-St Jeor Equation: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + (5 for men, -161 for women)
2. Revised Harris-Benedict Equation: A more modern update to the classic formula
3. Katch-McArdle Formula: Uses lean body mass for greater accuracy when body fat percentage is known
In addition to BMR calculation, this tool provides TDEE (Total Daily Energy Expenditure) based on your activity level, metabolic age estimation, 20-year BMR trend prediction, weight management simulation, macronutrient recommendations, and BMI-based health assessment.
Input range guidelines: Age 10-120 years, Height 120-250 cm (4'0" to 8'2"), Weight 30-300 kg (66-660 lbs).
- Multiple BMR formulas for comparison
- TDEE calculation for all activity levels
- Metabolic age estimation
- 20-year BMR trend prediction
- Weight management simulation
- Personalized macronutrient breakdown
- BMI-based health assessment
Frequently Asked Questions
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain basic vital functions like breathing, circulation, and cell production. It represents about 60-70% of your total daily calorie expenditure.
How does BMR change with age?
BMR typically decreases by about 1-2% per decade after age 30, mainly due to the natural loss of muscle mass. Regular strength training can help mitigate this decline.
What's the difference between BMR and TDEE?
BMR is the calories burned at rest. TDEE (Total Daily Energy Expenditure) includes BMR plus calories burned through physical activity and digestion. TDEE is your actual daily calorie needs.
Can exercise increase my BMR?
Yes! Regular strength training builds muscle mass, and muscle burns more calories at rest than fat. Aerobic exercise also has short-term metabolic benefits through EPOC (Excess Post-Exercise Oxygen Consumption).
How accurate is BMR calculation?
Equations provide good estimates, but actual BMR can vary by ±10% due to genetics, hormonal factors, health conditions, and recent nutrition. Direct measurement requires specialized equipment.
Example calculation for a 30-year-old male?
For a 30-year-old male, 70 kg, 175 cm: Mifflin-St Jeor BMR = 10×70 + 6.25×175 - 5×30 + 5 = 700 + 1093.75 - 150 + 5 = 1648.75 calories. With moderate activity, TDEE = 1648.75 × 1.55 = 2555 calories.
References & Scientific Sources
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.
- Mayo Clinic: Metabolism and weight loss
- Johnstone AM, Murison SD, Duncan JS, Rance KA, Speakman JR. Factors influencing variation in basal metabolic rate include fat-free mass, fat mass, age, and circulating thyroxine but not sex, circulating leptin, or triiodothyronine. Am J Clin Nutr. 2005;82(5):941-948.