For adults who are 5 feet 6 inches tall, a healthy BMI ranges from 18.5 to 24.9. This means a weight between 122 and 168 pounds for most people.
Body Mass Index (BMI) uses height and weight to estimate body fat. The formula divides weight in pounds by height in inches squared, then multiplies by 703:
BMI = (Weight in lbs / (Height in inches x Height in inches)) x 703For a 5'6" person weighing 145 pounds, the calculation would be:
(145 / (66 x 66)) x 703 = 22.9This places them in the "normal" category (18.5-24.9).
| Category | BMI Range | Weight Range for 5'6" |
|---|---|---|
| Underweight | Below 18.5 | Below 122 lbs |
| Normal | 18.5-24.9 | 122-168 lbs |
| Overweight | 25-29.9 | 169-209 lbs |
| Obese | 30 or higher | 210 lbs or more |
BMI doesn't account for muscle mass, bone density, or fat distribution. A muscular 5'6" athlete might register as overweight despite having low body fat. Conversely, someone with a normal BMI could carry excess visceral fat, increasing health risks.
Research published in the International Journal of Obesity found that BMI misclassifies up to 40% of people as healthy when they aren't. This is why doctors often combine BMI with other measurements like waist circumference or body fat percentage.
A BMI below 18.5 may indicate malnutrition or an eating disorder. A BMI above 30 increases the risk of heart disease, diabetes, and certain cancers. However, even within the "normal" range, extreme ends (e.g., 18.5 vs. 24.9) can have different health implications.
I once had a client with a BMI of 22 who struggled with energy levels due to low muscle mass. After adjusting her diet and exercise routine to build lean muscle, she felt better at the same weight.
Waist-to-height ratio (waist size ≤ height size) and body fat percentage (men: 10-20%; women: 20-30%) are more accurate indicators of health risks. Tools like bioelectrical impedance scales or DEXA scans measure body composition directly.
For a deeper examine BMI's limitations, read about why BMI is flawed.