What your body burns at rest, in calories per day.

Where the numbers come from

Mifflin-St Jeor was published in 1990 (Am J Clin Nutr) and adopted by the Academy of Nutrition and Dietetics evidence review in 2005 as the most accurate predictive equation for resting metabolic rate in healthy non-obese adults. Within Canadian dietetic practice, this is the equation that gets used to set baseline calorie targets before any activity multiplier is applied.

BMR vs RMR vs TDEE

BMR is the strict laboratory measurement — fasted, resting, thermoneutral. Resting Metabolic Rate (RMR) is what most consumer devices and home calculators actually estimate, and it runs about 5–10% higher than true BMR because subjects haven’t fasted overnight. TDEE adds activity on top. For practical use, treat BMR and RMR as roughly the same number unless you’re a clinician.

What this number doesn’t tell you

Predictive equations work poorly for people with very high or low body fat, substantial muscle mass relative to body weight, thyroid disease, or recent dramatic weight loss. If your BMR matters clinically — e.g. for managing an eating disorder, post-bariatric surgery, or medication-assisted weight management — get an indirect-calorimetry measurement, not a calculator estimate.