BMI (Body Mass Index) is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). It's a screening tool used to categorize weight status in adults.

BMI has limitations. It doesn't distinguish between muscle and fat mass, so athletes or very muscular individuals may have high BMI despite being healthy. It's also less accurate for older adults, children, and certain ethnic groups.

If your BMI is outside the normal range, consider consulting with a healthcare professional. They can provide personalized advice based on your overall health, body composition, and medical history.

For most adults, checking BMI monthly or quarterly is sufficient. If you're actively trying to lose or gain weight, weekly measurements can help track progress, but daily fluctuations are normal and not always meaningful.

BMI calculations for children and teens (ages 2-19) use age and sex-specific percentiles rather than the adult categories. Consult pediatric growth charts and healthcare providers for accurate assessment in young people.