BMI Calculator

Calculate your Body Mass Index (BMI) to assess if you're in a healthy weight range.

Calculate Your BMI

Metric (kg/cm)
Your BMI—

BMI Categories

Underweight
< 18.5
May indicate malnutrition or health issues
Normal
18.5 – 24.9
Healthy weight range for most adults
Overweight
25.0 – 29.9
May increase risk of health problems
Obese
≥ 30.0
Higher risk of serious health conditions
Note: BMI is a screening tool and doesn't directly measure body fat or health.
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Understanding Body Mass Index (BMI) & Health

Body Mass Index (BMI) is an internationally recognized screening metric used by physicians and healthcare organizations to evaluate weight-related health risks.

World Health Organization (WHO) BMI Weight Categories

BMI Range Weight Classification Health Risk Profile
< 18.5 Underweight Risk of nutritional deficiency, weakened immunity, and osteoporosis.
18.5 – 24.9 Normal (Healthy) Lowest risk of developing chronic weight-related metabolic diseases.
25.0 – 29.9 Overweight Moderate risk of hypertension, high cholesterol, and pre-diabetes.
≥ 30.0 Obese (Class I, II, III) High risk of cardiovascular disease, stroke, type 2 diabetes, and sleep apnea.

The Standard Mathematical Formulas

Depending on your preferred unit system:

Metric: BMI = Weight (kg) ÷ [Height (m)]²
Imperial: BMI = [Weight (lbs) × 703] ÷ [Height (in)]²

Example: An adult weighing 70 kg who is 1.75 meters tall: 70 ÷ (1.75 × 1.75) = 22.86 BMI (Healthy Range).

Clinical Limitations of BMI

While BMI is an excellent general screening tool, it does not assess body composition directly:

  • Athletes & Muscle Mass: Dense muscular build can yield an "overweight" BMI despite healthy body fat percentages.
  • Elderly Adults: Older individuals naturally lose lean muscle mass, potentially masking excess body fat.
  • Fat Distribution: Visceral belly fat carries higher cardiovascular risk than subcutaneous fat on hips and thighs.

Frequently Asked Questions

Common questions regarding Body Mass Index, healthy weight ranges, and formulas.

According to the World Health Organization (WHO), a healthy BMI for both adult men and women ranges between 18.5 and 24.9. A score below 18.5 indicates underweight, 25.0 to 29.9 indicates overweight, and 30.0 or higher indicates obesity.

In the Metric system, BMI = weight (kg) ÷ [height (m)]². For Imperial measurements, BMI = [weight (lbs) × 703] ÷ [height (inches)]².

No. BMI measures total excess weight rather than excess body fat. Because dense muscle weighs more than fat, highly muscular individuals and athletes may register as overweight or obese despite possessing low body fat.

Standard adult WHO BMI categories are identical for men and women. However, women naturally carry a higher percentage of essential body fat than men at the exact same BMI score.

A high BMI (overweight or obese) significantly increases the statistical risk of cardiovascular disease, high blood pressure (hypertension), type 2 diabetes, sleep apnea, joint osteoarthritis, and certain cancers.