BMR Calculator
Calculate your Basal Metabolic Rate (BMR) - the number of calories your body burns at rest - and see your daily needs by activity level.
What is BMR and why does it matter?
BMR (Basal Metabolic Rate) is calories your body burns at complete rest for basic functions: breathing, circulation, cell production, temperature regulation. It's 60-75% of total daily calories. Knowing BMR helps set accurate calorie goals - eat below BMR too long = slow metabolism, muscle loss. Most people need BMR x activity multiplier (TDEE) for daily needs. Higher muscle mass = higher BMR.
How accurate is the Mifflin-St Jeor equation?
Mifflin-St Jeor is most accurate BMR formula for general population (+-10% accuracy). More accurate than older Harris-Benedict equation. However, individuals vary - factors affecting actual BMR: Genetics, muscle mass, hormone levels, medications, diet history. Use calculated BMR as starting point, adjust based on real-world results. Track weight for 2-3 weeks to verify accuracy.
Can I increase my BMR?
Yes! Ways to boost BMR: Build muscle (muscle burns 6 cal/lb/day vs 2 cal/lb fat), don't crash diet (preserves metabolism), eat enough protein (thermic effect of food), stay hydrated, get quality sleep, manage stress, eat spicy foods (temporary boost), drink coffee/tea (mild effect). Strength training is most effective. Losing weight decreases BMR, so maintain muscle during fat loss.
What activity multiplier should I use?
Be honest about activity: Sedentary (1.2): Desk job, minimal movement. Light (1.375): Light exercise 1-3 days, walking. Moderate (1.55): Exercise 3-5 days, active job. Active (1.725): Exercise 6-7 days or physical job. Very Active (1.9): Athlete, very physical job. Most overestimate - if unsure, start lower. Exercise burns less than you think (3-5 workouts/week = light to moderate).