BMI Calculator

Calculate Body Mass Index from weight in kilograms and height in centimeters. Instant WHO classification from Severely Underweight through Obese Class III.

Enter your measurements

Type your weight in kilograms and height in centimeters. The calculator applies the standard BMI formula: weight divided by height squared.

Interpret the WHO category

Results include a named category based on World Health Organization thresholds. Categories range from Severely Underweight below 16 to Obese Class III above 40.

Understand BMI limitations

BMI does not distinguish muscle from fat. Athletes with high muscle mass may report elevated BMI despite excellent fitness. Use BMI as a screening indicator, not a diagnosis.

Review the numeric output

The JSON result includes your exact BMI rounded to one decimal, the category label, your entered weight in kg and height converted to meters.

BMI Calculator FAQs

BMI overestimates body fat in muscular individuals because it cannot differentiate between lean mass and fat tissue.
The WHO classifies a BMI between 18.5 and 24.9 as Normal Weight for most adult populations.