Calculate your Body Mass Index and healthy weight range.
Metric:
Imperial:
BMI is a screening tool, not a medical diagnosis. It does not account for muscle mass, bone density, fat distribution, or age variations.
Example 1 (Metric): 175 cm, 70 kg
BMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9 — Normal Weight
Example 2 (Imperial): 5'9", 160 lbs
BMI = 703 × 160 ÷ (69)² = 112,480 ÷ 4,761 = 23.6 — Normal Weight
Common Questions
Body Mass Index (BMI) is one of the most widely used health screening metrics in the world. Our free BMI calculator for men and women supports both metric (kg/cm) and imperial (lbs/ft/in) measurements and instantly categorizes your result using WHO standard ranges.
For adults aged 18 and over, the World Health Organization defines BMI categories as: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), Obese Class I (30.0–34.9), Obese Class II (35.0–39.9), and Obese Class III (40.0 and above).
The standard BMI formula and healthy range thresholds are identical for men and women. However, women naturally carry slightly more body fat than men at the same BMI due to physiological differences. This is why BMI is a screening tool rather than a definitive health assessment. For example, an athletic man with significant muscle mass might have a BMI in the "Overweight" range despite having excellent cardiovascular fitness.
For ages 2–19, pediatric BMI is assessed differently. Instead of fixed ranges, children's BMI is compared against age- and sex-specific growth charts. Results are expressed as percentiles: below the 5th percentile indicates underweight, 5th–84th is healthy weight, 85th–94th is overweight, and 95th percentile and above indicates obesity.
BMI has well-documented limitations: it doesn't distinguish between muscle and fat (athletes may show "overweight" despite low body fat); it doesn't capture fat distribution (visceral fat around the abdomen is more dangerous than subcutaneous fat); it can overestimate risk in certain ethnic groups; and it may underestimate risk in others. Always use BMI alongside waist circumference and other health markers for a complete picture.
If your BMI falls outside the normal range, consult your healthcare provider before making lifestyle changes. They can assess your full picture including body composition, metabolic health, and family history. Small, sustainable changes — a daily 30-minute walk, reducing processed food intake, prioritizing sleep — are more effective long-term than drastic interventions.
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