How Do You Calculate the Normal Weight for Your Age and Height?
The most common way to determine the normal weight for age and height is by calculating body mass index, states the Centers for Disease Control and Prevention. There are a number BMI calculators available online, including one on the Medical News Today website.
Body mass index is calculated by dividing a person's weight in kilograms by the square of his height in meters. A BMI between 18.5 and 24.9 for adults over 20 years of age is considered normal, according to the CDC. The differences in body fat increase among children and teens; therefore, age and sex are stronger factors for calculating BMI in people under 20. Although BMI can be used as an acceptable guide, many experts criticize the formula as flawed. A BMI does not take a person's bone density or muscle mass into account. It does not measure fat directly or diagnose impending health risks associated with weight.
A number of other recommended methods for determining an ideal weight are available, as listed on Medical News Today. Waist-to-hip ratio is calculated by dividing the lowest waist circumference by the widest part of the hips. Waist-to-height ratio charts optimal girth based on height. Most gyms and doctors' offices offer a more scientific approach for calculating body fat percentage, using techniques such as dual-energy X-ray absorptiometry and bioelectrical impedance analysis.