BMR Calculator

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. It typically accounts for 60-75% of daily calorie expenditure. Knowing your BMR helps you understand your minimum calorie needs and create effective nutrition plans for weight loss or gain.

The most accurate formula is the Mifflin-St Jeor equation. 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. For example, a 30-year-old man, 180cm, 80kg: BMR = (10 × 80) + (6.25 × 180) - (5 × 30) + 5 = 1,780 calories/day.

BMR is calories burned at complete rest, while TDEE (Total Daily Energy Expenditure) includes all daily activities. TDEE = BMR × activity factor. Activity factors range from 1.2 (sedentary) to 1.9 (extremely active). If your BMR is 1,600 calories and you're moderately active (factor 1.55), your TDEE is approximately 2,480 calories.

Eating below BMR is not recommended. Your body needs these calories for basic survival functions. Severe restriction can slow metabolism, cause muscle loss, and create nutrient deficiencies. For healthy weight loss, eat between your BMR and TDEE, creating a 300-500 calorie deficit. This promotes fat loss while preserving muscle mass.

Key factors include: Age (BMR decreases about 2% per decade after 20), Muscle mass (more muscle = higher BMR), Sex (men typically have 5-10% higher BMR), Genetics, Hormones (thyroid levels significantly impact BMR), and Body temperature. You can increase BMR through strength training to build muscle and by getting adequate sleep.