Joan Lunden
  Health Videos
as of September 23, 2017

Real Stories, Expert Advice

Safety Minute: Bike Safety & Helmets

A single rule – wearing a helmet when you bike – can reduce the risk of head injury by as much as 85 percent. The statistics are staggering. Over 130 deaths of kids on bikes every year and almost 300,000 injuries. Many which could...

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Health Tools & Resources

Body Mass Index Calculator

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About the Body Mass Index

BMI is a ratio of your weight to your height.

Nearly all adults with a high BMI have extra body fat; those with a low BMI often have too little body fat.

A normal BMI for kids and teens depends on age, and is not the same for adults over age 18.

Diagnostic Status and Risk According to Body Mass Index (BMI).*
For adults over age 18.
Status BMI Category
Risk of developing
health problems**
Underweight <18.5 Increased
Normal Weight 18.5 - 24.9 Least
Overweight 25.0 - 29.9 Increased
Obese Class I 30.0 - 34.9 High
Obese Class II 35.0 - 39.9 Very high
Obese Class III ≥40.0 Extremely high

*Note: Exceptions: For persons 65 years and older the 'normal' range may begin slightly above BMI 18.5 and extend into the 'overweight' range; very muscular athletes and body builders often have high BMIs and are not overfat; children and teens, who need an age appropriate scale; and pregnant and lactating women.

**If your risk is increased, speak with your doctor about having your cholesterol, triglycerides, blood sugar and blood pressure levels as part of a full cardiovascular and diabetes screen.

Adapted from: World Health Organization. (2000). Obesity: Preventing and Managing the Global Epidemic: Report of a WHO Consultation on Obesity. Geneva: WHO, page 9