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How It Works
Three simple steps to understand your BMI and metabolic health.
Enter Your Stats
Weight, height, age, and sex. Choose imperial (lbs/ft) or metric (kg/cm) — both supported.
Get Your BMI
Instantly see your BMI number, category, and where you land on the visual scale.
Discover Metabolic Age
See how your metabolism compares to your real age — and how to lower it.
Frequently Asked Questions
What is BMI and how is it calculated?+
BMI (Body Mass Index) uses your weight and height to estimate body fat. The formula is: weight (kg) ÷ height (m)². For imperial: (weight in lbs ÷ height in inches²) × 703. A BMI of 18.5–24.9 is considered healthy for most adults.
What is a healthy BMI range?+
For adults, the CDC considers a BMI of 18.5 to 24.9 healthy. Below 18.5 is underweight, 25.0–29.9 is overweight, and 30.0+ is obese. These ranges apply to most adults but may differ for athletes, the elderly, or specific ethnic groups.
What is metabolic age and why does it matter?+
Metabolic age compares your basal metabolic rate to the average for someone your chronological age. A metabolic age higher than your real age can signal lower lean mass or activity. A lower metabolic age suggests your habits are doing the work.
Is BMI accurate for muscular people?+
BMI does not distinguish muscle from fat. Athletes and bodybuilders often score 'overweight' or 'obese' despite low body fat. Use BMI alongside waist circumference, body fat percentage, and how you feel.
Can I lower my metabolic age?+
Yes. Build lean muscle through resistance training, increase daily steps, prioritize protein at meals, sleep 7–9 hours, and stay consistent. Sustainable habits beat crash diets every time.
Learn More About BMI & Health
Educational guides written for everyday readers.
⚠️ Important Disclaimer: The American BMI Calculator is an educational tool. BMI and metabolic age estimates are general indicators only and do not replace evaluation by a licensed healthcare professional. Always consult your physician before making health decisions.