About BMR Calculator
Calculate Your Basal Metabolic Rate
Our free BMR calculator uses the scientifically validated Mifflin-St Jeor equation to accurately calculate your Basal Metabolic Rate. BMR represents the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. Understanding your BMR is the first step toward effective weight management and achieving your fitness goals.
How to Use the BMR Calculator
- Select your biological sex (male or female)
- Enter your age in years (15-100)
- Input your height in centimeters or feet/inches
- Enter your current weight in kilograms or pounds
- Choose your activity level from sedentary to extremely active
- Click "Calculate BMR" to see your results
Understanding Your Results
BMR (Basal Metabolic Rate): This is the minimum number of calories your body needs to function at rest. It accounts for 60-75% of your total daily calorie expenditure and represents the energy required for essential bodily functions.
TDEE (Total Daily Energy Expenditure): This is your BMR multiplied by your activity level factor. TDEE represents the total calories you burn in a day, including all physical activities. Use this number to plan your calorie intake for weight maintenance, loss, or gain.
The Mifflin-St Jeor Equation
The Mifflin-St Jeor equation is considered the most accurate BMR calculation method for modern populations. Developed in 1990, it replaced the older Harris-Benedict equation and provides more precise results:
- For Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5
- For Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) − 161
Activity Level Multipliers
- Sedentary (1.2): Little or no exercise, desk job
- Lightly Active (1.375): Light exercise or sports 1-3 days per week
- Moderately Active (1.55): Moderate exercise or sports 3-5 days per week
- Very Active (1.725): Hard exercise or sports 6-7 days per week
- Extremely Active (1.9): Very hard exercise, physical job, or training twice per day
Using BMR for Weight Management
Weight Maintenance: Consume calories equal to your TDEE to maintain your current weight.
Weight Loss: Create a calorie deficit by consuming 250-1000 calories less than your TDEE. A deficit of 500 calories per day typically results in 1 pound of weight loss per week.
Weight Gain: Create a calorie surplus by consuming 250-500 calories more than your TDEE for gradual, healthy weight gain.
Factors Affecting BMR
- Age: BMR decreases by approximately 2% per decade after age 20
- Sex: Men typically have higher BMR than women due to greater muscle mass
- Body Composition: Muscle tissue burns more calories than fat tissue
- Genetics: Some people naturally have faster or slower metabolisms
- Hormones: Thyroid hormones significantly impact metabolic rate
- Temperature: Cold environments can temporarily increase BMR
Tips for Healthy Metabolism
- Build Muscle: Strength training increases muscle mass, which raises your BMR
- Stay Active: Regular physical activity boosts your TDEE and overall calorie burn
- Eat Enough Protein: Protein has a higher thermic effect than carbs or fats
- Don't Crash Diet: Severe calorie restriction can slow your metabolism
- Stay Hydrated: Proper hydration supports optimal metabolic function
- Get Enough Sleep: Poor sleep can negatively affect metabolism and hunger hormones
Frequently Asked Questions
Is BMR the same as metabolism?
BMR is a component of your metabolism. It represents the calories burned at rest, while total metabolism includes BMR plus calories burned through activity and digestion.
How accurate is the BMR calculator?
The Mifflin-St Jeor equation is accurate for most people, with an error margin of about 10%. Individual variations exist due to genetics, body composition, and other factors.
Should I eat my BMR calories?
No, you should eat your TDEE calories (BMR × activity level) for weight maintenance. Eating only BMR calories would create too large a deficit for most people.
Can I increase my BMR?
Yes, building muscle through strength training is the most effective way to increase BMR. Muscle tissue burns more calories at rest than fat tissue.