BMI Calculator

Calculate your Body Mass Index (BMI) with our free online calculator. Enter your weight and height to instantly determine your BMI and health category. Works with both metric (kg/cm) and imperial (lbs/inches) units.

Frequently Asked Questions

BMI (Body Mass Index) is a measure of body fat based on height and weight. It's calculated by dividing weight in kilograms by height in meters squared. BMI is used to screen for weight categories that may lead to health problems.

BMI categories are: Underweight (below 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (30 and above). These ranges may vary slightly for different populations and age groups.

BMI has limitations. It doesn't distinguish between muscle and fat mass, so athletes may have high BMI despite low body fat. It also doesn't account for fat distribution. Consider BMI as one health indicator among many.

A healthy BMI is generally considered to be between 18.5 and 24.9. However, optimal BMI may vary based on factors like age, ethnicity, and muscle mass. Consult a healthcare provider for personalized advice.

For children and teens aged 2-19, BMI is age and sex-specific using percentiles rather than fixed categories. The BMI-for-age percentile shows how a child's BMI compares to other children of the same age and sex. Always consult a pediatrician for accurate interpretation of children's BMI.

BMI is a simple screening tool based only on height and weight, not body composition. It cannot distinguish between muscle, bone, and fat mass. Bodybuilders and athletes often have high BMI due to muscle density, yet low body fat. For more accurate assessment, consider body fat percentage measurements or waist circumference.

Yes, BMI cutoff points may vary by ethnicity. Asian populations may have higher health risks at lower BMI values (overweight at 23 instead of 25). Some Pacific Islander populations may be healthy at higher BMI values. These differences reflect variations in body composition and disease risk patterns among ethnic groups.

Higher BMI increases risk of type 2 diabetes, heart disease, stroke, certain cancers, osteoarthritis, sleep apnea, and liver disease. However, BMI alone doesn't determine health status. Other factors like diet quality, physical activity, genetics, and fat distribution also significantly impact health outcomes.

Yes, BMI below 18.5 is considered underweight and may indicate malnutrition, eating disorders, or other health conditions. Low BMI can lead to weakened immune system, osteoporosis, anemia, and fertility issues. If your BMI is very low, consult a healthcare provider to identify underlying causes.

Consult a healthcare provider if your BMI is outside the healthy range, if you've experienced sudden weight changes, if you have obesity-related health conditions, or before starting a weight management program. A doctor can assess your overall health, body composition, and provide personalized recommendations beyond BMI alone.