Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain essential functions—breathing, circulation, cell repair, and nervous system operation. Calculating BMR is foundational to understanding your energy needs and making informed decisions about nutrition, fitness, and weight management.
Our BMR Calculator uses the Mifflin-St Jeor equation, one of the most accurate modern formulas, and optionally estimates your Total Daily Energy Expenditure (TDEE) based on activity level. This foundation empowers you to design sustainable nutrition plans and track progress toward health goals.
BMR is the foundation for calculating calorie needs. It enables accurate TDEE estimation and sustainable nutrition planning for any goal.
BMR is measured under strict lab conditions (fasted, complete rest). RMR is measured in typical conditions and is slightly higher. Used interchangeably in practice.
Mifflin-St Jeor was developed using modern populations and typically provides closer estimates. Both are estimates; individual variation always exists.
Build lean muscle through resistance training, ensure adequate protein/sleep, manage stress, maintain consistent activity. Each kg of muscle raises BMR modestly.
Weight directly enters the BMR formula. Additionally, aggressive deficits trigger adaptive thermogenesis where the body conserves energy.
Short-term yes, but chronically eating below BMR risks muscle loss, nutrient deficiency, hormonal disruption. Use moderate deficits (10-25% below TDEE) for sustainability.
Thyroid hormones regulate metabolic rate. Hypothyroidism reduces BMR; hyperthyroidism elevates it. Discuss thyroid screening if results seem off.
After ~5% weight change or significant lifestyle shifts (new training, medication). Quarterly or semi-annual checks suffice for most people.
Yes. BMR declines ~2-8% per decade after 30 due to lean muscle loss and hormonal changes. Resistance training and adequate protein help offset decline.
TDEE is BMR multiplied by activity factor. It estimates total daily calorie burn including exercise, NEAT, and digestion. Use TDEE to create deficits or surpluses.