BMR Calculator: Find Your Basal Metabolic Rate in Seconds
Discover your body's energy needs at rest with our comprehensive BMR calculator guide. Learn the science behind metabolism, compare different formulas, and optimize your nutrition plan.
What is Basal Metabolic Rate (BMR)?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic physiological functions like breathing, circulation, cell production, and brain function. It represents 60-75% of your total daily calorie expenditure.
Understanding your BMR is crucial for creating effective nutrition plans, whether you're looking to lose weight, gain muscle, or maintain your current physique. It's the foundation for calculating your Total Daily Energy Expenditure (TDEE).
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Calculate My BMR NowBMR Calculation Formulas Compared
Mifflin-St Jeor Equation
Most accurate and widely used formula
Harris-Benedict Equation
Classic formula, slightly less accurate
Katch-McArdle Formula
Uses body fat percentage for accuracy
Mifflin-St Jeor Equation - Detailed Analysis
The Mifflin-St Jeor equation is considered the gold standard for BMR calculation. It's more accurate than older formulas and works well for most populations.
Mifflin-St Jeor Formula:
Weight in kg, height in cm, age in years
✅ Advantages:
- Most accurate for modern populations
- Accounts for lean body mass
- Widely validated
⚠️ Considerations:
- Requires accurate weight and height measurements
Factors That Affect Your BMR
Age
Decreases BMR by 1-2% per decade after 20
Metabolism naturally slows with age due to muscle loss and hormonal changes
Gender
Men typically have 5-10% higher BMR
Men generally have more muscle mass and higher testosterone levels
Body Composition
Muscle burns 3x more calories than fat
Lean muscle tissue is metabolically active even at rest
Genetics
Can vary BMR by ±200-400 calories
Some people naturally have faster or slower metabolisms
Pro Tips for Accurate BMR Calculation
Measure Accurately
Use a digital scale and measure height without shoes for precise calculations
Test in the Morning
Measure weight first thing in the morning for consistent results
Consider Body Composition
If you know your body fat percentage, use the Katch-McArdle formula
Track Changes
Recalculate BMR every 4-6 weeks or after significant weight changes
BMR vs TDEE: What's the Difference?
BMR (Basal Metabolic Rate)
- Calories burned at complete rest
- 60-75% of total daily calories
- Foundation for TDEE calculation
TDEE (Total Daily Energy Expenditure)
- BMR + all daily activities
- What you should use for meal planning
- Includes exercise and daily movement
Related Calculators
Frequently Asked Questions
How accurate are BMR calculators?
BMR calculators are 90-95% accurate for most people. The Mifflin-St Jeor equation is considered the most accurate, while the Katch-McArdle formula is most precise when body fat percentage is known.
Can I increase my BMR?
Yes! Building muscle mass through strength training is the most effective way to increase your BMR. Other factors include getting adequate sleep, staying hydrated, and eating enough protein.
Should I eat below my BMR?
Never eat below your BMR for extended periods. Your BMR represents the minimum calories needed for basic bodily functions. Instead, create a moderate deficit from your TDEE.
Ready to Calculate Your BMR?
Now that you understand the science behind BMR calculation, you're ready to determine your body's energy needs at rest. Use this knowledge as the foundation for creating an effective nutrition plan that supports your health and fitness goals.