BMI Calculator
Calculate Body Mass Index
Frequently Asked Questions
How is BMI calculated and what do the numbers mean?
BMI is calculated as weight in kilograms divided by height in meters squared: BMI = weight(kg) / height(m)². Results are categorized as: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), Obese (30+).
Is BMI an accurate measure of health for everyone?
BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat mass, so athletes may show high BMI despite being healthy. It also does not account for age, gender, or body fat distribution. Use it as one indicator alongside other health metrics.
What is a healthy BMI range for adults?
The World Health Organization defines a healthy BMI as 18.5 to 24.9 for adults. For example, a person 170cm tall with a healthy BMI weighs between 53.5kg and 72kg. Optimal BMI may vary by ethnicity and age.
How does BMI differ for children and teenagers?
For children aged 2-20, BMI is interpreted using age-and-sex-specific percentile charts rather than fixed thresholds. A child at the 85th-95th percentile is considered overweight, and above the 95th percentile is obese.
Can BMI be used to set weight loss goals?
Yes. If your BMI is above 25, you can calculate your target weight for a healthy BMI. For example, at 180cm tall, a BMI of 24.9 corresponds to 80.7kg. Aim for gradual weight loss of 0.5-1kg per week for sustainable results.