Adult BMI and Daily Energy Estimate
Calculate adult BMI and estimate daily energy expenditure from age, sex and activity. This is not a body-fat measurement, diagnosis or dietary prescription.
Moderate exercise (3–5x/week)
Enter adult age (18–120), height (100–250 cm) and weight (25–350 kg). Outside this range, seek an individual assessment.
Note: Based on Korean obesity standards. Mifflin-St Jeor formula.
Frequently Asked Questions
Q. What does BMI calculate?
Body weight in kilograms divided by height in metres squared. At 170 cm and 70 kg it is about 24.2. It does not measure body fat or muscle mass.
Q. Why do classification thresholds differ?
Korean adult criteria use 23 to below 25 for pre-obesity and 25 or more for obesity. International comparisons often use 25 and 30. Neither classification alone diagnoses an individual.
Q. Is energy expenditure measured?
No. The Mifflin–St Jeor equation estimates resting energy, then an activity multiplier estimates daily expenditure. Incorrect age or activity can materially change the result.
Q. Who needs a different assessment?
Children and adolescents need age-specific growth references. Pregnancy, breastfeeding, illness, disordered eating, age-related muscle loss and athletic physiques require individualized assessment.
Q. Will the suggested calories guarantee a weight change?
No. Water, muscle, actual activity and adaptation change outcomes. Gain/loss options and target dates are simplified illustrations, not dietary prescriptions.
Q. Is the macro split personalized?
No. It demonstrates conversion from calorie percentages to grams of carbohydrate, protein and fat. Protein needs depend separately on body weight, activity and health.
How to Use
Enter height, weight, age and the sex used by the equation.
Choose a realistic activity level and read the limits before interpreting the result.
Worked example: Adult BMI and Daily Energy Estimate
For a 35-year-old man at 170 cm and 70 kg, the equation is 10×70 + 6.25×170 − 5×35 + 5 = 1,592.5 kcal. Multiplying by 1.55 gives about 2,468 kcal. Choosing a different activity multiplier changes the estimate without changing body size. Use it as a starting point for individualized assessment and longer-term trends, not as a prediction of daily weight.