BMI Calculator
Estimate adult Body Mass Index using weight in kilograms and height in centimetres.
BMI is a screening measure, not a medical diagnosis.
Understanding BMI
BMI compares weight with height. It is commonly used as a broad adult screening measure, but it does not measure body composition or health directly.
How to use it
- Enter weight in kilograms.
- Enter height in centimetres.
- Select Calculate BMI.
Formula
BMI = weight in kilograms ÷ (height in metres)²
Example
Important limitations
Informational use only. BMI is not a diagnosis and may not reflect individual body fat, muscle mass or health risk. Adult categories are unsuitable for children and require careful interpretation during pregnancy, for athletes, older adults and different populations. Consult a qualified healthcare professional for personal advice.
BMI category thresholds shown here are general adult screening thresholds. They do not replace an individual clinical assessment.
Health reference: World Health Organization — Obesity and overweight. Source reviewed 28 September 2026.
Frequently asked questions
What is BMI?
It is a screening ratio based on weight relative to height.
Is BMI a diagnosis?
No. It cannot diagnose a condition or directly measure body fat.
Who should not rely on adult categories?
Children require age-specific assessment, while pregnancy, athletic builds and population differences require professional interpretation.