Basal Metabolic Rate is the number of calories your body burns just staying alive, awake, and maintaining core temperature and organ function.

Can you eat below your BMR?

Eating consistently below BMR is generally not recommended without physician supervision, as prolonged severe deficits trigger adaptive thermogenesis and loss of vital lean tissue.

Calories & BMRScope: Adults (18+)

BMR Calculator

Calculate Basal Metabolic Rate using the gold-standard Mifflin-St Jeor equation

Input Parameters

Real-time calculation updates dynamically as you adjust inputs. Values remain strictly local on your device.

Basal Metabolic RateMifflin-St Jeor Standard

1649kcal/day

Daily energy needed at absolute rest: ~69 kcal/hour

Harris-Benedict Estimate

1696kcal/day

Resting Burn per Hour

69kcal/h

Metric Energy

6899kJ/day

Estimated Energy Breakdown by Organ System

Liver

~27% of BMR

Continuous biochemical synthesis & detox

Brain

~19% of BMR

Neuronal ion pumping & neurotransmission

Skeletal Muscle

~18% of BMR

Resting tone & protein turnover

Kidneys

~10% of BMR

Continuous renal filtration

Heart

~7% of BMR

Uninterrupted cardiac pumping

Other Organs

~19% of BMR

Gastrointestinal, adipose, skin turnover

Clinical Responsibility Note: This calculation provides statistical estimations for informational and educational purposes only. It is not an individualized medical diagnosis or clinical prescription.

Mathematical Formula & Scientific Methodology

Formula: Mifflin-St Jeor BMR Equation (1990)

Men: 10 × W + 6.25 × H - 5 × A + 5 | Women: 10 × W + 6.25 × H - 5 × A - 161

Recommended by the Academy of Nutrition and Dietetics as the most reliable predictive formula for non-ventilated individuals.

Model Assumptions

Healthy thermo-neutral post-absorptive state
Absence of acute fever or severe thyroid disorder

Variables & Standard Units

Symbol	Physiological Meaning	Unit
W	Weight in kilograms	kg
H	Height in centimeters	cm
A	Age in years	years

Scientific Limitations

Muscular athletes may have higher BMR due to greater lean muscle mass

Peer-Reviewed Scientific Citations

A new predictive equation for resting energy expenditure in healthy individuals (1990)

Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990) — The American Journal of Clinical Nutrition, 51(2), 241-247

Key Finding: Mifflin-St Jeor equation is accurate within ±10% of measured REE in non-obese and obese individuals, recommended by the Academy of Nutrition and Dietetics as the most reliable standard equation.

The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass (1984)

Roza AM, Shizgal HM (1984) — The American Journal of Clinical Nutrition, 40(1), 168-182

Key Finding: Revised coefficients for the classical Harris-Benedict formula adjusting for modern anthropometric datasets.

Frequently Asked Questions

Related Calculators & Next Steps

Calories & BMR

TDEE Calculator

Total Daily Energy Expenditure based on physical activity level and BMR

Calculate now

Calories & BMR

Calorie Calculator

Calculate daily calorie requirements tailored for weight loss, maintenance, or muscle gain

Calculate now

Calories & BMR

Resting Metabolic Rate Calculator

Calculate resting metabolic rate (RMR) with optional Cunningham lean mass calibration

Calculate now