What is BMI Calculator?
BMI (Body Mass Index) is a numerical measure derived from an individual's weight and height. Introduced by Adolphe Quetelet, it classifies individuals into weight categories to identify potential risk factors for obesity-related health conditions.
How to Use BMI Calculator
- 1Select your preferred unit system: Metric (kilograms & centimeters) or Imperial (pounds, feet & inches).
- 2Select your age and gender (used for context in WHO guidelines).
- 3Enter your current height and body weight.
- 4Click "Calculate BMI" to view your score, visual gauge indicator, WHO category, and optimal target weight range.
How Does BMI Calculator Work?
The calculation divides total body weight in kilograms by the square of height in meters. In imperial units, weight in pounds is divided by height in inches squared, multiplied by a conversion factor of 703.
Metric: BMI = weight (kg) / [height (m)]² | Imperial: BMI = [weight (lbs) / height (in)²] × 703Practical Examples
Metric BMI Calculation
Height: 175 cm (1.75 m), Weight: 70 kg.
Imperial BMI Calculation
Height: 5 ft 10 in (70 inches), Weight: 160 lbs.
Frequently Asked Questions
What are the standard WHO BMI categories?
Underweight: < 18.5 | Normal weight: 18.5 – 24.9 | Overweight: 25.0 – 29.9 | Obesity: 30.0 or greater.
Is BMI accurate for athletes and bodybuilders?
BMI does not distinguish between muscle mass and body fat. Athletes with high muscle mass may be classified as "overweight" or "obese" despite having very low body fat.
Does BMI apply equally to men and women?
The standard adult BMI formula is identical for men and women. However, women naturally tend to carry more essential body fat than men at the same BMI.
What is considered a healthy BMI range?
For adults aged 20 and over, a BMI between 18.5 and 24.9 is considered normal and associated with lower health risks.
Can children use this BMI calculator?
Child and adolescent BMI requires age-and-gender percentiles (BMI-for-age charts). This calculator is optimized for adults aged 18 and older.