Body Adiposity Index (BAI) Calculator
Estimate body-fat percentage with the Body Adiposity Index (BAI) from hip circumference and height — no scale needed — and see the healthy range for your age and sex.
How it works
BAI = hip circumference (cm) ÷ height (m)^1.5 − 18
The Body Adiposity Index was developed by Bergman and colleagues (Obesity, 2011) in Mexican-American and African-American adults and validated against DXA. Unlike BMI it does not use weight: hip circumference and height alone give a number that reads directly as an estimated body-fat percentage. Later studies found it less accurate than hoped at the extremes of body size, so treat it as one estimate among several.
Worked example
A 35-year-old man, 175 cm tall with a 100 cm hip: 1.75^1.5 = 2.315, so BAI = 100 ÷ 2.315 − 18 = 25.2%. His healthy range (men 20–39) is 8–21%, so 25.2% falls in the Overweight band (21–26%).
Sources: Bergman RN et al. A better index of body adiposity. Obesity 2011 · Gallagher D et al. Healthy percentage body fat ranges. Am J Clin Nutr 2000
Frequently asked questions
Is BAI more accurate than BMI?
BAI estimates body fat directly and needs no scale, but large validation studies found it no better than BMI overall, and it tends to overestimate fat in lean men and underestimate it in people with high body fat. It is useful as a quick second opinion.
Where do I measure my hips?
Around the widest part of the buttocks with feet together, the tape level and snug but not compressing the skin.
What is a healthy BAI?
For adults aged 20–39 about 8–21% for men and 21–33% for women; the ranges rise slightly with age (see the table).
Related calculators
This calculator gives an estimate for general fitness and education only. It is not a diagnosis — results from field tests and prediction equations can differ from laboratory measurements, so talk to a doctor or qualified exercise professional before acting on them.