BMI Chart

How to Read the BMI Chart

The BMI chart displays a grid of heights and weights with the corresponding BMI value in each cell. Find your height in the left column, then scan across to your weight to see your BMI. Cells are color-coded: blue for underweight, green for normal, yellow for overweight, orange for obese class I, and red for obese class II and III.

How BMI Is Calculated

Body Mass Index is calculated by dividing a person's weight in kilograms by their height in meters squared:

BMI = weight (kg) ÷ height (m)²

In imperial units, the formula is:

BMI = (weight in lbs × 703) ÷ (height in inches)²

For example, a person who weighs 160 pounds and is 5 feet 10 inches (70 inches) tall has a BMI of (160 × 703) ÷ (70²) = 112,480 ÷ 4,900 = 22.95.

BMI Categories Explained

Underweight (Below 18.5)

Being underweight may indicate malnutrition, an underlying health condition, or excessive exercise. Risks include weakened immune function, osteoporosis, anemia, and fertility issues. Consult a healthcare provider if your BMI falls below 18.5.

Normal Weight (18.5 – 24.9)

A BMI in this range is generally associated with the lowest health risks. Maintaining a normal BMI through balanced nutrition and regular physical activity supports cardiovascular health, joint health, and overall well-being.

Overweight (25.0 – 29.9)

Being overweight increases the risk of type 2 diabetes, hypertension, heart disease, and sleep apnea. Modest weight loss of 5-10% of body weight can significantly improve health markers. Focus on sustainable diet and exercise changes.

Obese (30.0 and Above)

Obesity significantly increases the risk of chronic diseases including type 2 diabetes, cardiovascular disease, certain cancers, and joint problems. Medical intervention may include lifestyle changes, medication, or surgery depending on severity and comorbidities.

Limitations of BMI

• Muscle mass: Athletes may have a high BMI due to muscle weight, not fat.
• Age: Older adults tend to have more body fat at the same BMI as younger adults.
• Sex: Women typically have more body fat than men at the same BMI.
• Ethnicity: Health risks at different BMI levels vary by ethnic group.
• Body fat distribution: BMI does not measure where fat is stored. Abdominal fat carries higher health risks than fat stored in hips and thighs.

BMI is a useful screening tool, but it should be used alongside other health assessments like waist circumference, body fat percentage, blood pressure, and blood work to provide a complete picture of health status. Always consult a healthcare professional for personalized advice.