BMR Calculator
Basal metabolic rate
About This Calculator
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic life functions — breathing, circulation, cell production, and organ function. It represents your minimum calorie requirement and is the foundation for calculating total daily energy needs. BMR accounts for 60-75% of total energy expenditure in sedentary individuals.
Formula
Mifflin-St Jeor (recommended): BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + s (s=+5 for men, −161 for women)
Harris-Benedict (original): Men: 66.47 + 13.75×kg + 5.003×cm − 6.755×age
Katch-McArdle: BMR = 370 + 21.6×LBM (LBM = lean body mass in kg)
Example Calculation
30-year-old male, 80 kg, 180 cm
- BMR = 10×80 + 6.25×180 − 5×30 + 5
- = 800 + 1125 − 150 + 5 = 1,780 kcal/day
BMR = 1,780 calories/day at rest
BMR by Weight and Height (Male, Age 30, Mifflin-St Jeor)
| Weight | 160 cm | 170 cm | 180 cm | 190 cm |
|---|---|---|---|---|
| 60 kg | 1,425 | 1,488 | 1,550 | 1,613 |
| 70 kg | 1,525 | 1,588 | 1,650 | 1,713 |
| 80 kg | 1,625 | 1,688 | 1,750 | 1,813 |
| 90 kg | 1,725 | 1,788 | 1,850 | 1,913 |
| 100 kg | 1,825 | 1,888 | 1,950 | 2,013 |
Frequently Asked Questions
What is the difference between BMR and RMR?
BMR is measured under very strict conditions (fasting, complete rest, thermoneutral environment). Resting Metabolic Rate (RMR) is slightly less strict and typically runs 10-20% higher than BMR. For practical purposes they are used interchangeably.
Does muscle mass affect BMR?
Yes significantly. Muscle tissue burns more calories at rest than fat. Adding muscle through resistance training increases BMR, making it easier to maintain a healthy weight. This is why BMR declines with age as muscle mass naturally decreases.
How accurate is the BMR formula?
The Mifflin-St Jeor equation is accurate to within 10% for most people. It may underestimate BMR for very muscular individuals (whose extra lean mass burns more) and overestimate for obese individuals. For precision, use the Katch-McArdle formula with body fat measurement.
Does dieting affect BMR?
Yes — severe caloric restriction causes metabolic adaptation, where the body reduces BMR by 15-30% to conserve energy. This is why crash dieting often leads to a 'plateau.' Gradual deficits and maintaining muscle mass minimize this effect.