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Body adiposity index (BAI) calculator
Short answer
The body adiposity index estimates body fat percentage from hip circumference and height alone: BAI = hip (cm) ÷ height (m)^1.5 − 18. A 100 cm hip at 170 cm gives a BAI of 27.1%. It needs no scale, and its authors found it most accurate above about 20% body fat.
Last reviewed 28 October 20261 published sourcesNot medical advice
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| Hip | 160 cm | 170 cm | 180 cm |
|---|---|---|---|
| 85 cm (33 in) | 24.0 | 20.3 | 17.2 |
| 95 cm (37 in) | 28.9 | 24.9 | 21.3 |
| 105 cm (41 in) | 33.9 | 29.4 | 25.5 |
| 115 cm (45 in) | 38.8 | 33.9 | 29.6 |
| 125 cm (49 in) | 43.8 | 38.4 | 33.8 |
Where the formula comes from
Bergman and colleagues looked for the simple measurements that best tracked DXA body fat in 1,733 Mexican-American adults. Hip circumference and height stood out, and hip ÷ height^1.5 − 18 matched body fat percentage closely (Bergman et al., 2011).
They then tested it in a separate group of African-American adults, where it correlated with DXA body fat at R = 0.85. It was least accurate at low body fat, below about 20% (Bergman et al., 2011).
Other ways to estimate body fat
Compare it with the US Navy tape method in the body fat calculator, or with the waist-based relative fat mass calculator.
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Common questions
How is the body adiposity index calculated?
BAI = hip circumference in cm ÷ (height in metres)^1.5 − 18. The result reads directly as an estimate of body fat percentage, with no separate formula for men and women.
How accurate is BAI?
In the African-American adults it was tested on, BAI correlated with DXA-measured body fat at R = 0.85. Its authors found it tracked body fat best above about 20%, so it is less reliable for lean people.
Is BAI better than BMI?
It answers a different question. BMI needs weight and does not separate fat from muscle; BAI needs only a tape and a height and was built to estimate body fat directly. Neither measures fat itself.
Sources
Figures on this page were checked against these publications on 28 October 2026.
- Bergman RN, Stefanovski D, Buchanan TA, Sumner AE, Reynolds JC, Sebring NG, Xiang AH, Watanabe RM. A better index of body adiposity. Obesity (Silver Spring). 2011;19(5):1083–1089. doi.org/10.1038/oby.2011.38
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- Body fat calculatorBody fat percentage from a tape measure with the US Navy equations.
- Lean body mass calculatorLean mass from height and weight with three equations, or from your body fat.