Category
Fitness
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BMI Categories
Underweight BMI < 18.5
Normal weight BMI 18.5 - 24.9
Overweight BMI 25.0 - 29.9
Obese BMI 30+
How BMI Works
Body Mass Index (BMI) compares weight relative to height. It is widely used as a screening measure for adult weight status.
- Imperial formula: (weight in pounds / height in inches^2) * 703.
- Metric formula: weight in kilograms / height in meters^2.
- Healthy weight range is based on BMI 18.5 to 24.9.
- BMI does not directly measure body fat or muscle mass.
Examples
Balanced profile
5'9" and 160 lbs
BMI 23.6 (Normal weight)
Higher range profile
6'0" and 200 lbs
BMI 27.1 (Overweight)
Metric profile
170 cm and 70 kg
BMI 24.2 (Normal weight)
Frequently Asked Questions
Is BMI accurate for everyone?
BMI is useful for population screening, but it can misclassify people with high muscle mass or unusual body composition.
What is a healthy BMI?
For most adults, 18.5 to 24.9 is considered healthy.
Should I use BMI alone?
No. Use BMI with waist measurements, activity, diet, and guidance from a healthcare professional.
How often should I check BMI?
Monthly or quarterly trends are more useful than day-to-day changes.