Compute your Body Mass Index using international metric units (centimeters and kilograms). Fast, private, and client-side.
Enter your height and weight below for an immediate, private calculation.
The metric calculation of Body Mass Index is the purest form of the anthropometric equation because it requires zero conversion factors:
Because height is usually measured in centimeters (cm), convert your height to meters by dividing by 100 before squaring (e.g., 180 cm = 1.80 m).
Standard international adult reference ranges. Note that BMI is an epidemiological screening metric and should be evaluated alongside individual clinical indicators.
| Category | BMI Range (kg/m²) | Classification Status | General Health Assessment |
|---|---|---|---|
| Severe Thinness | < 16.0 | Underweight (Severe) | Elevated risk of nutrient deficiencies and low bone mineral density |
| Moderate Thinness | 16.0 – 16.9 | Underweight (Moderate) | Increased risk of nutritional compromise and fatigue |
| Mild Thinness | 17.0 – 18.4 | Underweight (Mild) | Mild risk; may be typical for some lean body types |
| Normal / Healthy Weight | 18.5 – 24.9 | Healthy Weight | Statistically lowest correlation with weight-related chronic conditions |
| Pre-Obesity / Overweight | 25.0 – 29.9 | Overweight | Slightly elevated cardiovascular and metabolic risk; evaluate body composition |
| Obesity Class I | 30.0 – 34.9 | Obesity (Class 1) | Moderate risk of hypertension, dyslipidemia, and type 2 diabetes |
| Obesity Class II | 35.0 – 39.9 | Obesity (Class 2) | Severe risk of cardiovascular complications and sleep apnea |
| Obesity Class III | ≥ 40.0 | Obesity (Class 3 / Severe) | Very severe health risk; comprehensive clinical management recommended |
Clinical context: These cutoffs apply to adults age 20 and older. Some health organizations (such as the WHO Asian expert consultation) suggest alternative cutoffs (such as overweight beginning at 23.0 and obesity at 27.5) for populations with differing body fat distributions.
Find clear, evidence-based answers to common questions about Body Mass Index calculation, accuracy, and interpretation.
First, convert your height from centimeters into meters by dividing by 100 (e.g., 170 cm = 1.70 m). Next, square the height in meters (1.70 × 1.70 = 2.89). Finally, divide your weight in kilograms by that number (e.g., 68 kg ÷ 2.89 = 23.53).