BMI Calculator
Free bmi calculator — updated for 2025. Accurate, instant, no sign-up needed.
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BMI Calculator
Body Mass Index for adults — US & Metric units
Your BMI
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Category
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Healthy Weight Range
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Underweight <18.5Normal 18.5–24.9Overweight 25–29.9Obese ≥30
What Is BMI?
Body Mass Index measures body fat based on height and weight. It's a screening tool but doesn't account for muscle mass, bone density, or fat distribution.
BMI = weight(kg) / height(m)² · BMI (US) = 703 × weight(lbs) / height(in)²
BMI Categories (WHO)
- Underweight: BMI < 18.5 · Normal: 18.5–24.9 · Overweight: 25.0–29.9 · Obese: 30+
⚠️ BMI is a screening tool, not a diagnostic measure. Consult a healthcare provider for a complete assessment.
Is BMI accurate for athletes?
Not always — muscle weighs more than fat. Athletes may have a high BMI despite low body fat. Waist circumference and body fat % are better metrics for athletic individuals.