Understanding Your BMI of 17.7
A BMI of 17.7 at 5'9" and 120 pounds places you in the “Underweight”category. BMI (Body Mass Index) is a screening tool that estimates body fat based on height and weight. It's calculated by dividing weight in pounds by height in inches squared, then multiplying by 703.
BMI = (120 ÷ 69²) × 703 = 17.7
For your height of 5'9", a healthy weight (BMI 18.5 to 24.9) falls between 125 and 169 pounds. To reach the lower end of the healthy range, you would need to gain approximately 5 pounds.
Keep in mind that BMI is a screening tool, not a diagnostic. It does not account for muscle mass, bone density, age, sex, or body composition. Athletes and muscular individuals often have a high BMI despite being healthy. Always consult a healthcare provider for a complete health assessment.