How to Calculate BMI: Formula, Chart, and What It Means

BMI (Body Mass Index) is a simple screening tool that uses your height and weight to estimate body fat. While it's not perfect, it's a useful starting point for understanding your weight category.

The BMI Formula

Metric: BMI = weight (kg) ÷ height (m)²

Imperial: BMI = (weight (lbs) ÷ height (in)²) × 703

For example, someone who is 175 cm tall and weighs 70 kg:

BMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9

BMI Categories

Limitations of BMI

BMI is a rough estimate. It doesn't account for:

• Muscle mass — athletes may have a high BMI but low body fat
• Body composition — two people with the same BMI can have very different body fat percentages
• Age and gender — BMI ranges were developed for adults and may not apply to children or elderly
• Ethnicity — health risks associated with BMI vary across populations

BMI is best used as a starting point, not a diagnosis. Consult a healthcare provider for a complete health assessment.

Calculate Your BMI

Use our free BMI Calculator to find your BMI instantly. It supports both metric and imperial units and shows you which category you fall into.