Estimate resting metabolic rate (RMR) and daily caloric needs using the Mifflin–St Jeor equation (1990), one of the most validated RMR formulas in clinical nutrition research.
Formula (RMR)
- Men: RMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: RMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Total daily energy expenditure depends on activity level; this tool applies a multiplier to RMR when an activity factor is selected.
Background
Mifflin–St Jeor replaced older Harris–Benedict estimates for many populations and is recommended by the Academy of Nutrition and Dietetics for RMR prediction when indirect calorimetry is unavailable.
When to use it
Useful for rough meal-planning targets, weight-loss or gain planning, and educational comparisons between activity levels—not for prescribing medical diets.
Limitations
Individual metabolism varies with genetics, thyroid function, medications, lean mass, and adaptive thermogenesis during prolonged dieting. The equation underestimates needs for very muscular individuals and may be less accurate in certain ethnic groups or clinical states. Indirect calorimetry remains the gold standard.
Health disclaimer
Caloric estimates are informational only and not personalized medical or dietary advice. Consult a registered dietitian or physician before significant calorie restriction, especially if you have diabetes, eating disorders, are pregnant, or take medications affecting metabolism.