BMI Calculator
Calculate Body Mass Index (BMI) with metric or imperial units and see your category, healthy range, and a visual scale.
What is BMI?
Body Mass Index (BMI) is a simple screening metric that compares your weight to your height. It is commonly used to categorize weight status in adults.
BMI formula explained
In metric units, BMI is calculated as weight (kg) / height² (m²). In imperial units, it can be calculated as (weight (lb) / height² (in²)) × 703.
BMI categories and meaning
WHO adult categories
- Underweight: < 18.5
- Normal: 18.5 – 24.9
- Overweight: 25.0 – 29.9
- Obese (Class I): 30.0 – 34.9
- Obese (Class II): 35.0 – 39.9
- Obese (Class III): ≥ 40
Limitations of BMI
BMI does not directly measure body fat and may be misleading for athletes, older adults, or people with unusual body composition. For personalized advice, consult a qualified healthcare professional.
Frequently Asked Questions
Quick answers about BMI.
What is BMI?
BMI (Body Mass Index) is a screening metric that relates weight to height to estimate weight category for adults.
How is BMI calculated?
Metric BMI = kg / m². Imperial BMI = (lb / in²) × 703.
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered a healthy range.
Is BMI accurate for everyone?
BMI can be less accurate for athletes, older adults, and children/teens because it does not measure body fat directly.
Should athletes use BMI?
Athletes may have high BMI due to muscle mass. Consider other measurements like waist size and body composition.
Disclaimer
This calculator is for informational purposes only and does not provide medical advice. BMI is a general screening tool and may not reflect individual health status.