BMI Calculator

How BMI is calculated

BMI (Body Mass Index) is calculated by dividing your weight by your height squared. It was developed by Belgian mathematician Adolphe Quetelet in the 19th century and adopted by health organisations as a population-level screening tool.

Frequently Asked Questions

• What is a healthy BMI?
  According to the WHO and CDC, a BMI of 18.5 to 24.9 is classified as healthy weight. Under 18.5 is underweight. 25 to 29.9 is overweight. 30 or above is obese.
• What are the limitations of BMI?
  BMI does not measure body fat directly and does not distinguish between muscle and fat mass. A muscular athlete may have an "overweight" BMI despite having low body fat. BMI also does not account for where fat is distributed, age-related muscle loss, or ethnic differences in body composition risk thresholds. Use BMI as one data point, not a complete health picture.
• How is BMI calculated?
  BMI = weight (kg) ÷ height (m)². In imperial units: BMI = (weight lbs × 703) ÷ (height in inches)².
• What weight should I be for my height?
  The healthy BMI range of 18.5–24.9 corresponds to different weights for different heights. For example, a 5'6" person has a healthy range of approximately 115–154 lbs. The calculator above shows your specific healthy weight range after you enter your height.