BMR Calculator
Basal Metabolic Rate

Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain basic physiological functions like breathing, circulation, and cellular repair. It represents 60-75% of your total daily energy expenditure and is crucial for understanding your baseline calorie needs for weight management and health planning.

The Mifflin-St Jeor equation is considered the most accurate for healthy individuals, with an accuracy rate of approximately ±10%. It's more precise than the older Harris-Benedict equation and is widely used by healthcare professionals and nutritionists for clinical applications.

First, multiply your BMR by your activity factor (1.2-1.9) to get Total Daily Energy Expenditure (TDEE). For safe weight loss, create a calorie deficit of 500-1000 calories per day below your TDEE, which results in 0.5-1kg weight loss per week. Never eat below your BMR for extended periods.

BMR calculations are estimates and can vary based on body composition (muscle burns more calories than fat), genetics, hormonal status, medical conditions (thyroid disorders), medications, and metabolic adaptations from dieting. People with more muscle mass typically have higher BMRs.

BMR (Basal Metabolic Rate) is measured under strict laboratory conditions after 8 hours of sleep, 12 hours of fasting, and in a controlled environment. RMR (Resting Metabolic Rate) is measured under less strict conditions and is typically 10-20% higher than BMR. For practical purposes, the terms are often used interchangeably.

BMR typically decreases by 2-3% per decade after age 20 due to loss of muscle mass, decreased physical activity, and hormonal changes. This is why the formula subtracts calories based on age. Maintaining muscle mass through strength training can help minimize this decline.

Men generally have higher muscle mass, larger body size, and different hormonal profiles that result in 10-15% higher BMR than women of similar age and weight. Muscle tissue burns significantly more calories at rest than fat tissue, contributing to this difference.

Yes! Strength training increases muscle mass, which raises BMR. High-intensity interval training (HIIT) can boost metabolism for hours after exercise. Adequate protein intake has a higher thermic effect, and staying hydrated and getting quality sleep also support optimal metabolic function.

Online BMR calculators using the Mifflin-St Jeor equation are accurate within ±10-15% for most healthy individuals. However, they don't account for individual variations in body composition or metabolic efficiency. For more precise measurements, consider professional metabolic testing using indirect calorimetry.

No, eating significantly below your BMR is not recommended for extended periods. This can lead to metabolic slowdown, muscle loss, nutrient deficiencies, and hormonal disruptions. Instead, create a moderate deficit from your TDEE (BMR × activity level) for sustainable, healthy weight loss.

Recalculate your BMR whenever you experience significant weight changes (5+ kg), major changes in body composition, or every 3-6 months during active weight management. Your BMR will change as your weight and body composition change, so regular updates ensure accurate calorie targets.

Thyroid disorders significantly impact BMR - hyperthyroidism increases it while hypothyroidism decreases it. PCOS, diabetes, hormonal imbalances, and certain medications can also affect metabolic rate. If you have medical conditions, consult healthcare providers for personalized calorie recommendations.