BAI Calculator
Calculate your Body Adiposity Index using height and hip circumference
Disclaimer: For informational purposes only. Not a substitute for professional medical advice. Always consult a healthcare provider for health-related decisions.
BAI Calculator
Contents
What is BAI?
The Body Adiposity Index (BAI) is a method of estimating the percentage of body fat in humans. It uses:
- Hip Circumference
- Height
BAI is designed to be a simple and accessible alternative to BMI, as it does not require weight measurements.
Published formula: BAI = hip circumference (cm) / height (m)^1.5 − 18. A 100 cm hip measurement and 170 cm height yield 27.12.
Bergman et al. (2011) developed this body-fat estimate in Mexican-American adults and checked it in an African-American adult cohort. The study did not establish individualized health grades from this estimate. Source checked 30 September 2026.
How to Measure
For accurate BAI calculation, measure:
- Height: Stand straight against a wall, without shoes
- Hip Circumference: Measure around the widest part of your hips, ensuring the tape is horizontal
Use the same measurement method and units for comparisons; the equation depends directly on the hip and height inputs.
Understanding Results
BAI is a population-derived body-fat estimate, not a measured percentage or personalized grade. The number 27.12 in the worked example is an equation output; no sex/age obesity or “healthy” tier is assigned.
The 2011 development cohort was BetaGene: 1,733 Mexican-American adults, including women studied after pregnancies with or without gestational diabetes and their relatives. The separate TARA check included 223 African-American adults aged 20–50. Findings in those cohorts do not establish accuracy for every population.
The form declines negative or nonfinite BAI outputs rather than clipping them. Arithmetic feasibility alone does not certify body-fat accuracy; no new clinical cutoff is introduced.
Frequently Asked Questions
How is BAI different from BMI?
BAI uses hip circumference in centimeters and height in meters; BMI uses mass in kilograms and height squared. Neither expression directly measures body fat.
Is BAI more accurate than BMI?
Freedman et al. (2012) compared BAI and other measures in 1,151 adults and did not find a general accuracy advantage over BMI, waist or hip. The title of the development paper is not a promise of superiority. Source checked 30 September 2026.
Who was the original estimate studied in?
Mexican-American BetaGene adults and African-American TARA adults. The form does not establish suitability for children, pregnancy or unusual body proportions.