BMI Calculator
Calculate your Body Mass Index and see what it means for your health
// Weight Targets
What Is BMI?
Body Mass Index (BMI) is a simple numerical measure of a person's weight in relation to their height. It is widely used as a screening tool to categorise weight status and identify potential health risks associated with being underweight or overweight.
BMI Formula
BMI Categories (WHO)
The World Health Organisation defines: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), Obesity Class I (30–34.9), Obesity Class II (35–39.9), Obesity Class III (40 and above).
Limitations of BMI
BMI does not distinguish between muscle and fat mass. Athletes and highly muscular individuals often have a high BMI despite low body fat. Similarly, BMI does not account for age-related changes in body composition, fat distribution (waist circumference is an important additional measure), or differences between ethnic groups. It is a useful screening tool but should not be used as a sole diagnostic measure.
BMI for Children
BMI categories for children and teenagers are age- and sex-specific, as body composition changes significantly with development. This calculator uses adult BMI categories. For children under 18, consult a healthcare professional for age-adjusted interpretation.
From the Blog
// Beyond BMI
Waist circumference is a stronger predictor of metabolic risk. Men: under 94 cm, women: under 80 cm is generally healthy.
// Muscle vs Fat
BMI cannot distinguish muscle from fat. A muscular athlete may show "overweight" BMI despite excellent health.
// Healthy Range
A BMI of 18.5–24.9 is associated with the lowest risk of weight-related health conditions in the general adult population.
// Trend Matters
The direction your BMI is moving matters as much as the number. A rising BMI over years is a more useful health signal.