BMR Calculator
Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure
Most accurate for general population. Recommended by nutritionists worldwide.
Moderate exercise 3-5 days/week (BMR × 1.55)
TDEE by Activity Level
How to Use the BMR Calculator
- Choose your preferred BMR formula (Mifflin-St Jeor recommended)
- Select your unit system (Metric or Imperial)
- Enter your gender, age, weight, and height
- For Katch-McArdle formula, also enter your body fat percentage
- Select your activity level to calculate TDEE
- View your BMR, TDEE breakdown, and macro recommendations
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body needs to maintain basic physiological functions like breathing, circulation, and cell production while at complete rest. It represents the minimum energy required to keep your body alive and functioning.
BMR Calculation Formulas
Mifflin-St Jeor Equation
Most accurate formula for general population. Recommended by most nutritionists and widely used in clinical settings.
Harris-Benedict Equation
Original BMR formula developed in 1919. Still widely used but slightly less accurate than Mifflin-St Jeor for modern populations.
Katch-McArdle Formula
Most accurate for lean individuals with known body fat percentage. Requires body fat measurement but provides precise results.
Understanding TDEE
TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. It represents the total calories you burn in a day including exercise and daily activities.
Sedentary (1.2x)
Little or no exercise, desk job
Light Activity (1.375x)
Light exercise 1-3 days per week
Moderate Activity (1.55x)
Moderate exercise 3-5 days per week
Active (1.725x)
Hard exercise 6-7 days per week
Very Active (1.9x)
Very hard exercise, physical job
BMR Tips & Guidelines
Choose the Right Formula
Mifflin-St Jeor is most accurate for general population. Use Katch-McArdle if you know your body fat percentage.
Be Honest About Activity
Overestimating activity level leads to weight gain. Choose the level that matches your actual daily movement.
BMR Changes With Age
Your BMR naturally decreases as you age due to loss of muscle mass. Recalculate periodically.
Use for Weight Management
Eat below TDEE for weight loss, above for weight gain, or at TDEE for maintenance.
Amazing BMR Facts
Fascinating facts about your metabolism and how your body uses energy at rest.
Brain Power Consumption
Your brain uses about 20% of your daily calories despite being only 2% of your body weight!
Heart Never Rests
Your heart burns approximately 440 calories per day just by beating continuously.
Metabolic Gender Gap
Men typically have 10-15% higher BMR than women due to greater muscle mass and body size.
Age Effect
BMR decreases by approximately 2% per decade after age 30 due to muscle mass loss.
Muscle is Expensive
Each pound of muscle burns 6-10 calories per day at rest, while fat burns only 1-3 calories.
Cold Burns Calories
Your BMR can increase by 15-20% in cold environments as your body works to maintain temperature.
Actionable Tips by BMR Category
Personalized action plans based on your BMR and TDEE to help optimize your metabolism and achieve your health goals.
Low BMR Action Plan
Immediate Steps
- Add strength training to build muscle mass
- Increase protein intake to support muscle growth
- Check for underlying thyroid issues
Short Term (1-3 months)
- Consistent resistance training 3-4x per week
- Avoid very low calorie diets that slow metabolism
- Include HIIT workouts to boost metabolism
Long Term (3+ months)
- Build significant muscle mass to increase BMR
- Maintain consistent exercise routine
- Monitor and adjust calorie intake as BMR improves
High BMR Action Plan
Immediate Steps
- Ensure adequate calorie intake to fuel metabolism
- Focus on nutrient-dense foods
- Maintain current muscle mass with strength training
Short Term (1-3 months)
- Optimize training for your higher energy needs
- Consider body composition goals over weight loss
- Monitor energy levels and adjust intake accordingly
Long Term (3+ months)
- Use high BMR advantage for muscle building
- Maintain active lifestyle to support metabolism
- Regular BMR recalculation as body changes
BMR Myths vs Reality
MYTH: Eating late slows your BMR
Reality: BMR remains constant regardless of meal timing. Total daily calories matter more than when you eat them.
MYTH: Supplements can significantly boost BMR
Reality: Most supplements have minimal impact on BMR. Building muscle and staying active are the most effective methods.
MYTH: Frequent small meals boost metabolism
Reality: Meal frequency doesn't significantly impact BMR. Total daily calorie intake and composition are more important.
MYTH: Cardio is best for boosting BMR
Reality: Strength training is more effective for long-term BMR increase by building metabolically active muscle tissue.
Frequently Asked Questions
How accurate are BMR calculations?
BMR formulas provide estimates within 10-20% for most people. Individual variations in metabolism, genetics, and body composition can affect accuracy.
Can I increase my BMR permanently?
Yes, building muscle mass through strength training is the most effective way to permanently increase your BMR, as muscle tissue burns more calories at rest.
Why is my BMR lower than expected?
Factors like genetics, thyroid function, previous dieting history, and body composition can all influence your actual BMR compared to calculated estimates.
Should I eat exactly my BMR calories?
No, BMR is the minimum for basic functions. You should eat your TDEE calories for maintenance, or adjust based on your weight goals.
How often should I recalculate my BMR?
Recalculate your BMR every 10-15 pounds of weight change, or every 6 months if your weight is stable but you're building muscle.
Which formula should I use?
Mifflin-St Jeor for general use, Harris-Benedict if comparing to older studies, and Katch-McArdle if you have accurate body fat measurements.
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