BMR Calculator
Calculate your basal metabolic rate and daily calorie needs
BMR Calculator
Mifflin-St Jeor equation — most accurate for general populations
Weight
Height
What is Basal Metabolic Rate?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain basic physiological functions like breathing, circulation, cell production, and nutrient processing. It's the minimum amount of energy your body needs just to survive.
BMR accounts for approximately 60-75% of your total daily energy expenditure, even if you're sedentary. The rest comes from your activity level and digestion. Understanding your BMR helps you set appropriate calorie targets for weight loss, maintenance, or muscle gain.
BMR vs TDEE: What's the Difference?
BMR (Basal Metabolic Rate)
Calories burned at rest with no activity
- Measured in controlled conditions
- Does not include activity
- Lower than actual daily burn
- Useful baseline for calculations
TDEE (Total Daily Energy Expenditure)
Total calories you burn in a day
- Includes BMR + activity
- Based on activity level
- What you actually burn daily
- Use this for calorie targets
The Mifflin-St Jeor Formula
This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for normal-weight to overweight individuals:
For Men:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
For Women:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
This formula accounts for weight, height, age, and gender, making it more accurate than older methods.
Factors That Affect Your BMR
Age
BMR decreases with age. After 30, you lose about 3-5% of muscle mass per decade, slowing metabolism.
Muscle Mass
Muscle tissue is more metabolically active than fat. Building muscle increases your BMR.
Gender
Men typically have higher BMR due to greater muscle mass. Women have 5-10% lower BMR on average.
Genetics
Genetics play a role in your BMR. Some people naturally have faster or slower metabolisms.
Thyroid Health
Thyroid hormones regulate metabolism. Thyroid issues can significantly increase or decrease BMR.
Diet & Exercise
Strength training builds muscle and boosts BMR. Crash diets lower it by causing muscle loss.
How to Use Your BMR
1. Calculate Your TDEE: Multiply your BMR by your activity factor to get your Total Daily Energy Expenditure. This is what you actually burn daily.
2. Set Calorie Targets:
- Weight Loss: TDEE - 500 calories (roughly 0.5 kg/week loss)
- Maintenance: TDEE calories (no change)
- Weight Gain: TDEE + 500 calories (roughly 0.5 kg/week gain)
3. Monitor Progress: Track your weight and energy levels for 2-3 weeks, then adjust your intake based on results. Your actual needs may differ from calculations.
4. Don't Go Too Low: Never eat significantly below your BMR for extended periods. This can cause muscle loss, metabolic adaptation, and nutrient deficiencies.
Disclaimer: This calculator provides estimates based on the Mifflin-St Jeor formula. Individual metabolic rates vary due to genetics, thyroid function, medication, and other factors. These calculations are not medical advice. Consult with a healthcare professional or registered dietitian for personalized nutrition guidance.