Body Mass Index (BMI) is a simple calculation using a person’s height and weight. The formula is: weight (kg) / [height (m)]² or (703 × weight in pounds) / (height in inches)² for imperial units.

BMI is a useful screening tool to categorize weight status in adults as underweight, normal weight, overweight, or obesity. However, it does not directly assess body fat or health.

Keep in mind that BMI may not be accurate for all individuals, such as athletes or the elderly, where muscle mass or other factors can skew results. Always consult a healthcare provider for comprehensive evaluation.