BMI Calculator
Calculate your Body Mass Index (BMI), World Health Organization (WHO) classification, ideal body weight range, BMI Prime, and Ponderal Index with instant metric and imperial support.
Body Metrics
175 cm
70 kg
Your BMI Score
22.9kg/m²
Normal Weight (Healthy Range)
Great job! Your BMI is within the healthy weight range for adults.
BMI Scale Spectrum12.0 – 40.0+
22.9
12.018.525.030.035.040.0+
Healthy Weight Range
56.7 kg – 76.3 kg
Target weight for BMI 18.5 – 24.9 at your height.
Weight Status Target
Your weight is currently within the recommended healthy range for your height.
BMI Prime Ratio
0.91
Ratio to upper healthy limit (25.0). Optimal ratio: 0.74 – 1.00.
Ponderal Index
13.06 kg/m³
Mass relative to height cubed. Normal range: 11.0 – 15.0 kg/m³.
WHO Body Mass Index Categories Reference Table
| BMI Range (kg/m²) | Classification | Primary Category |
|---|---|---|
| < 16.0 | Severe Thinness | Underweight |
| 16.0 – 16.9 | Moderate Thinness | Underweight |
| 17.0 – 18.4 | Mild Thinness | Underweight |
| 18.5 – 24.9 | Normal Weight | Healthy |
| 25.0 – 29.9 | Pre-obese | Overweight |
| 30.0 – 34.9 | Obesity Class I | Obese |
| 35.0 – 39.9 | Obesity Class II | Obese |
| ≥ 40.0 | Obesity Class III | Severe Obese |
Frequently asked questions
- What is Body Mass Index (BMI)?
- Body Mass Index (BMI) is a standardized health screening tool calculated by dividing a person’s body weight in kilograms by the square of their height in meters (kg/m²). It categorizes individuals into underweight, normal weight, overweight, and obesity ranges.
- What is a healthy BMI for adults?
- According to World Health Organization (WHO) standards for adult men and women, a healthy BMI ranges between 18.5 and 24.9. A BMI below 18.5 is considered underweight, 25.0 to 29.9 is overweight, and 30.0 or higher falls into obesity categories.
- What is the difference between Metric and Imperial BMI formulas?
- The Metric formula is BMI = weight (kg) / [height (m)]². The Imperial formula is BMI = 703 × weight (lbs) / [height (inches)]². Both formulas calculate identical BMI scores for equal physical dimensions.
- What is BMI Prime and Ponderal Index?
- BMI Prime is the ratio of your calculated BMI relative to the upper limit of normal BMI (25.0). A BMI Prime under 0.74 indicates underweight, 0.74 to 1.00 is normal weight, and over 1.00 indicates overweight. Ponderal Index measures mass relative to height cubed (kg/m³), which provides better scaling for very tall or very short individuals.
- Are there limitations to BMI accuracy?
- Yes. BMI is a general statistical indicator and does not directly measure body fat percentage, muscle mass, bone density, or fat distribution. Athletes and bodybuilders with high muscle mass may have a high BMI without excess fat, while elderly individuals may have lower muscle mass.