How to Calculate Your BMI (Body Mass Index) — Formula & Free Tool
The Body Mass Index (BMI) is an internationally recognized health metric used by the World Health Organization (WHO) to classify body weight relative to height.
The Official BMI Formula
Metric System:
BMI = Weight (kg) ÷ [Height (m)]²
Imperial System:
BMI = 703 × Weight (lbs) ÷ [Height (inches)]²
Official WHO BMI Categories
| BMI Score | Classification | Health Risk |
|---|---|---|
| < 18.5 | Underweight | Nutritional deficiency risk |
| 18.5 – 24.9 | Normal Weight | Lowest health risk |
| 25.0 – 29.9 | Overweight | Moderate risk |
| 30.0 & Above | Obese (Classes I, II, III) | Elevated metabolic risk |
Check Your BMI in 5 Seconds
Calculate your BMI score with personalized health tips and diet suggestions on Kalqr.
Calculate BMI NowFrequently Asked Questions
What is a healthy BMI for adults?
A healthy BMI score for most adults is between 18.5 and 24.9.
Is BMI accurate for muscular athletes?
BMI does not distinguish between muscle mass and fat mass, so bodybuilders may register as overweight despite having low body fat.