Scientific Protocol

Methodology & Science

How we calculate your results using the World Health Organization (WHO) international standards for universal health assessment.

The BMI Formula

Quetelet Index

BMI = weight(kg) / [height(m)]²

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, healthy weight, overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m²).

WHO Global Standards

This calculator adheres strictly to the World Health Organization (WHO) international classification. While some regional variations exist in clinical settings, a single global standard ensures consistency and clear goal-setting for users worldwide.

Classification	BMI Range (kg/m²)	Health Risk
Underweight	< 18.5	Increased
Normal weight	18.5 – 24.9	Minimal
Overweight	25.0 – 29.9	Increased
Obesity	≥ 30.0	High / Very High

Limitations

Muscle Mass

BMI does not distinguish between muscle and fat. Athletes may have a high BMI despite low body fat.

Bone Density

Older adults or those with bone density variations may see results that don't perfectly align with overall health.