BMR Calculator
Free online BMR calculator to calculate your Basal Metabolic Rate - the number of calories your body needs at rest. Calculate daily calorie needs with activity level multipliers using Harris-Benedict and Mifflin-St Jeor equations.
Calculate Your BMR
Activity Level Multipliers
| Activity Level | Description | Multiplier | Example |
|---|---|---|---|
| Sedentary | Little/no exercise | 1.2 | Desk job, no regular exercise |
| Light Activity | Light exercise 1-3 days/week | 1.375 | Light workouts, walking |
| Moderate Activity | Moderate exercise 3-5 days/week | 1.55 | Regular gym sessions |
| Active | Hard exercise 6-7 days/week | 1.725 | Daily intense workouts |
| Very Active | Very hard exercise, physical job | 1.9 | Athlete, construction worker |
BMR Examples by Age and Gender
| Age Group | Male BMR (avg) | Female BMR (avg) | Notes |
|---|---|---|---|
| 20-30 years | 1800-2000 cal | 1400-1600 cal | Peak metabolic rate |
| 30-40 years | 1750-1950 cal | 1350-1550 cal | Slight decline begins |
| 40-50 years | 1700-1900 cal | 1300-1500 cal | Noticeable decline |
| 50-60 years | 1650-1850 cal | 1250-1450 cal | Continued decline |
| 60+ years | 1600-1800 cal | 1200-1400 cal | Lower metabolic rate |
BMR and TDEE Guidelines
About BMR (Basal Metabolic Rate)
BMR is the number of calories your body needs to maintain basic physiological functions at rest, such as breathing, circulation, cell production, nutrient processing, and protein synthesis.
BMR Calculation Formulas
- Mifflin-St Jeor (Men): BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5
- Mifflin-St Jeor (Women): BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161
- Harris-Benedict (Men): BMR = 88.362 + 13.397 × weight(kg) + 4.799 × height(cm) - 5.677 × age
- Harris-Benedict (Women): BMR = 447.593 + 9.247 × weight(kg) + 3.098 × height(cm) - 4.330 × age
Factors Affecting BMR
- Age: BMR decreases with age (about 2% per decade after 30)
- Gender: Men typically have higher BMR than women
- Body composition: More muscle mass = higher BMR
- Genetics: Some people naturally have faster metabolism
- Hormones: Thyroid hormones significantly affect BMR
- Temperature: Cold environments can increase BMR
Using BMR for Weight Management
- BMR represents minimum calories needed for survival
- TDEE (BMR × activity level) shows total daily calorie needs
- Create calorie deficit below TDEE for weight loss
- Never eat below BMR for extended periods
Frequently Asked Questions
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body needs to maintain basic physiological functions at rest, such as breathing, circulation, and cell production.
How is BMR calculated?
BMR is calculated using formulas like Harris-Benedict or Mifflin-St Jeor equations, which consider age, gender, height, and weight to estimate daily caloric needs at rest.
What's the difference between BMR and TDEE?
BMR is calories needed at rest, while TDEE (Total Daily Energy Expenditure) includes BMR plus calories burned through physical activity and exercise.
Can I eat below my BMR?
Eating significantly below BMR for extended periods can slow metabolism and cause muscle loss. It's generally recommended to eat between BMR and TDEE for sustainable weight loss.