How this BMR and TDEE calculator works
The Mifflin–St Jeor equation estimates resting energy expenditure from weight, height, age, and sex. TDEE then multiplies that estimate by the selected activity factor. “BMR” is commonly used by consumers, although the equation predicts resting energy expenditure rather than a laboratory basal measurement.
female resting estimate = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161TDEE = resting estimate × activity multiplierUnderstanding your results
The result is a starting estimate, not a calorie prescription. Activity multipliers and prediction equations introduce uncertainty. Actual needs can be assessed more directly with indirect calorimetry or inferred over time from consistent intake, weight trends, and clinical context.
Menopause and metabolic change
Research associates the menopausal transition with changes in fat-free mass, body-fat distribution, activity, and energy expenditure, but effects differ between individuals. No validated universal “menopause adjustment” belongs in this equation. Thyroid disease, medications, sleep, symptoms, illness, and dieting history also matter.
Muscle-mass preservation
CDC guidance emphasizes muscle-strengthening activity as people age. Protein needs and resistance training should be individualized, especially with kidney disease, osteoporosis, frailty, injury, or other conditions. This calculator cannot set a safe deficit or nutrition plan.
Frequently asked questions about metabolism after 50
Does menopause slow metabolism?
Energy expenditure and body composition can change through menopause, but there is no single calorie amount that applies to every woman. Age, lean mass, activity, sleep, symptoms, medications, illness, and dietary intake influence observed changes. A formula should show uncertainty rather than invent a hormonal correction.
How accurate is the Mifflin–St Jeor equation?
It is a population prediction equation, so individual error is expected. Published reviews often discuss accuracy within roughly 10% for many adults, but error may be larger with unusual body composition, frailty, illness, major weight change, or conditions outside the original study population.
Should I eat below BMR to lose weight?
BMR is not a universal minimum intake or a treatment threshold. Aggressive restriction can increase nutritional risk and loss of lean tissue. Weight-management decisions should consider medical history, medications, bone and muscle health, eating-disorder risk, and professional guidance.