Body Adiposity Index (BAI) Calculator
Estimate body fat percentage using hip circumference and height. BAI helps when scale measurements are unavailable or unreliable.
Measurements
Record hip circumference at the widest point of the buttocks while standing.
BAI Result
Body Adiposity Index
29.2%
Sex
female
Hip circumference
100.0 cm • 39.4 in
Height
165.0 cm • 65.0 in
Interpretation
Healthy body fat range for adult women.
How to Use This Calculator
Measure hip girth
Stand upright with feet together. Wrap a flexible tape around the widest part of the buttocks. Record to the nearest centimeter or quarter inch.
Record height
Use a wall-mounted stadiometer. Stand straight, heels together, and measure without shoes. Enter height in centimeters or inches.
Interpret BAI
Compare the percentage with the provided interpretation to gauge whether your body fat falls in the healthy range.
Formula
BAI = (Hip Circumference in cm ÷ Height1.5 in m) − 18
- The formula does not require body weight, unlike BMI.
- Hip circumference is measured at the fullest part of the buttocks.
- Height must be converted to meters and raised to the 1.5 power.
- The resulting value approximates body fat percentage.
Example: Hip = 100 cm, Height = 1.65 m ⇒ BAI = 100 ÷ 1.651.5 − 18 ≈ 29.3%.
Understanding Body Adiposity Index
The Body Adiposity Index was developed as an alternative to BMI that relies on hip circumference instead of body weight. It can be especially helpful when scales are unavailable or weight fluctuates rapidly—such as in heart failure or fluid shifts.
While BAI correlates with body fat percentage measured by DXA scans, it still has limitations. It may underestimate adiposity in very muscular individuals and overestimate it when hip measurements are larger due to gluteal muscle mass rather than fat. Use the index alongside other health markers for a comprehensive picture.
Frequently Asked Questions
How accurate is BAI compared to BMI?
BAI can better reflect body fat percentage in some populations because it uses hip circumference. However, accuracy varies with ethnicity, age, and body shape. Consider it one data point among many.
Do I need to account for clothing?
Measure over lightweight clothing or directly on the skin for consistency. Bulky garments will inflate the hip circumference.
Is BAI suitable for athletes?
Athletes with high muscle mass around the hips may receive higher BAI values. Combine BAI with skinfolds, DXA, or bioimpedance for better accuracy.
Can I track progress with BAI?
Yes. Measure under the same conditions each time—same tape placement, time of day, and posture—to monitor changes over weeks or months.