BMR Calculator
Calculate your Basal Metabolic Rate to understand how many calories your body burns at rest and plan your nutrition effectively.
Calories burned at complete rest
Total daily energy expenditure
Your BMR is the number of calories your body burns at rest to maintain vital functions. Your TDEE accounts for your activity level and represents the total calories you burn daily.
Extreme Weight Loss
-2 lbs/week (not recommended)
Moderate Weight Loss
-1 lb/week
Mild Weight Loss
-0.5 lb/week
Maintenance
Maintain current weight
Mild Weight Gain
+0.5 lb/week
Moderate Weight Gain
+1 lb/week
Based on maintenance calories with a balanced 30/40/30 split
What is BMR?
BMR (Basal Metabolic Rate) represents the number of calories your body needs to perform basic life-sustaining functions while at complete rest. These functions include breathing, blood circulation, cell production, nutrient processing, and temperature regulation.
Your BMR accounts for approximately 60-75% of your total daily calorie expenditure, making it a crucial factor in understanding your body's energy needs and planning effective nutrition strategies for weight management.
BMR Formulas
Mifflin-St Jeor Equation (Recommended)
Men
BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) + 5
Women
BMR = (10 × weight kg) + (6.25 × height cm) - (5 × age) - 161
Harris-Benedict Equation (Original)
Men
BMR = 88.36 + (13.4 × weight kg) + (4.8 × height cm) - (5.7 × age)
Women
BMR = 447.6 + (9.2 × weight kg) + (3.1 × height cm) - (4.3 × age)
TDEE Activity Multipliers
To calculate your Total Daily Energy Expenditure (TDEE), multiply your BMR by your activity level:
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.2 |
| Lightly Active | Light exercise 1-3 days/week | 1.375 |
| Moderately Active | Moderate exercise 3-5 days/week | 1.55 |
| Very Active | Hard exercise 6-7 days/week | 1.725 |
| Extremely Active | Hard daily exercise & physical job | 1.9 |
Factors That Affect BMR
Age
BMR decreases approximately 1-2% per decade after age 20
Gender
Men typically have higher BMR due to greater muscle mass
Body Composition
More muscle mass means higher BMR since muscle burns more calories
Genetics
Inherited traits can influence metabolic rate by up to 10%
Hormones
Thyroid hormones, cortisol, and others affect metabolism
Climate
Extreme temperatures can temporarily increase BMR
How to Boost Your Metabolism
- Build Muscle: Strength training increases muscle mass, which burns more calories at rest than fat tissue.
- Stay Active: Regular physical activity, even light movement throughout the day, keeps your metabolism elevated.
- Eat Enough Protein: Protein has a higher thermic effect, meaning your body burns more calories digesting it.
- Stay Hydrated: Drinking cold water can temporarily boost metabolism as your body heats it to body temperature.
- Get Adequate Sleep: Poor sleep is linked to decreased metabolic rate and increased hunger hormones.
- Don't Crash Diet: Severe calorie restriction can significantly lower BMR as your body adapts to conserve energy.
Frequently Asked Questions
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. It represents the minimum energy your body needs to survive.
What is the difference between BMR and TDEE?
BMR is the calories burned at rest, while TDEE (Total Daily Energy Expenditure) includes all calories burned throughout the day, including physical activity and exercise. TDEE = BMR × Activity Factor.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is considered the most accurate for most people, developed in 1990. The Harris-Benedict equation (1918) tends to overestimate calorie needs, especially for overweight individuals.
How do I use BMR for weight loss?
To lose weight, eat fewer calories than your TDEE. A deficit of 500 calories per day leads to about 1 pound of weight loss per week. Never eat below your BMR as this can slow metabolism and cause muscle loss.
Does BMR change with age?
Yes, BMR typically decreases with age due to loss of muscle mass and hormonal changes. After age 20, BMR decreases by about 1-2% per decade. Regular strength training can help maintain muscle mass and BMR.
Related Calculators
For more scientific information about basal metabolic rate and energy expenditure, visit the Wikipedia article on Basal Metabolic Rate.