Body Mass Index (BMI) is the most widely used screening tool for weight categories. Here’s everything you need to know about how it’s calculated and what it means.
The BMI Formula
BMI = weight (kg) / height (m)²
For imperial units: BMI = (weight in pounds × 703) / (height in inches)²
BMI Categories
| Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obese | 30 and above |
Example Calculation
A person weighing 70 kg with height 170 cm (1.70 m): BMI = 70 / (1.70 × 1.70) = 70 / 2.89 = 24.2 (Normal weight)
Limitations
BMI doesn’t measure body fat directly. Athletes with high muscle mass may be classified as overweight despite being healthy. Always consult healthcare professionals for comprehensive health assessment.
Calculate Your BMI
Use our free BMI Calculator for instant results with personalized category recommendations.