BMI Calculator | Free Engine
Instant medically-calibrated BMI score. Calculate your weight category using metric or imperial units.
Body Mass Index (BMI) screens whether your weight falls in a healthy range for your height. It's calculated as BMI = weight(kg) / height(m)², with under 18.5 classified as underweight, 18.5–24.9 as healthy, 25–29.9 as overweight, and 30+ as obese.
Current BMI
22.9
Target Weight Range
125lbs - 168lbs
Height Context
5'9"
Metrics
Strategy Note
BMI is a screening tool, not a diagnostic. A high BMI should be paired with a waist-to-hip ratio measurement for a full metabolic profile.
Start Macro AuditMetabolic Status
WHO Classification Gauge
Healthy
You are in the optimal range.
The Mathematics of Body Mass Index
The BMI formula was developed in the 19th century by Adolphe Quetelet. It remains the global standard for rapid health screening due to its high correlation with metabolic disease markers across large populations.
For the official classification ranges and guidance on using BMI as a screening tool, see the CDC's Adult BMI Calculator and guidance.
The Quetelet Formula
Clinical Inquiries
?Is BMI accurate for athletes?
Not always. BMI doesn't distinguish between muscle and fat. Athletes with high muscle mass may be classified as overweight despite low body fat.
?How can I lower my BMI?
Focus on a consistent caloric deficit and strength training to preserve muscle while losing fat.