Calculate your Body Mass Index (BMI) instantly. Supports both metric (kg/cm) and imperial (lb/ft) units. Free, no login required.
Body Mass Index (BMI) is a measure of body fat based on height and weight. It is used by healthcare professionals worldwide as a quick screening tool to identify potential weight problems.
The formula is: BMI = weight(kg) / height(m)²
While BMI is a useful general indicator, it doesnt distinguish between muscle and fat, and doesnt account for age, sex, or ethnicity. Always consult a healthcare provider for personalized advice.
A BMI between 18.5 and 24.9 is considered normal/healthy. Under 18.5 is underweight, 25–29.9 is overweight, and 30+ is obese according to WHO standards.
BMI is a general screening tool. It may overestimate body fat in muscular people and underestimate it in older adults. Athletes, pregnant women, and children need different assessments.
BMI = weight (kg) ÷ height² (m²). For example: 70kg ÷ (1.75m × 1.75m) = 22.9 BMI. In imperial: BMI = (weight lbs × 703) ÷ height² (inches²).
For adults 20+, the same BMI scale applies regardless of age. For children and teens (2–19), BMI is interpreted using age and sex-specific growth charts (BMI-for-age percentile).
Overweight is BMI 25–29.9 and indicates excess body weight but not necessarily excess fat. Obese is BMI 30+ and carries higher health risks including diabetes, heart disease, and hypertension.