How to use it
- Enter your Height in centimetres.
- Measure your Hip circumference around the widest part of your hips and enter it in centimetres.
- Read the Body adiposity index (BAI) and the Estimated body fat, and check the working under The working, step by step.
How the index is calculated
Bergman and colleagues (2011) proposed the body adiposity index to estimate body fat without weighing. It uses only the hip circumference and the height: the hip circumference divided by the height to the power 1.5, minus 18. The hip and the height were chosen because hip circumference and height are both strongly correlated with percentage body fat in their data.
The authors checked the index against body fat measured by DXA scanning in two study groups, African Americans and Mexican Americans, and reported that it reflects body fat for adult men and women of differing ethnicities without numerical correction. The index is an estimate and not medical advice. A doctor assesses body fat and health risk, using waist measurements, blood tests or a scan where needed.
BAI = hip circumference (cm) / height (m)^1.5 - 18
Example: hip 95 cm, height 1.65 m: 95 / 1.65^1.5 - 18 = 26.8What the number means
Bergman and colleagues fitted the index to percentage body fat and found that the two are nearly equal, so a BAI of 26.8 corresponds to about 26.8 percent body fat in their data. They did not publish cut-off values for calling a result low, normal or high, so this page does not put you in a category.
Freedman and colleagues (2012) later found that the BAI was not more accurate than body mass index, waist circumference or hip circumference alone for estimating body fat. For a category, the body fat calculator gives the American Council on Exercise ranges, and your doctor can say what a result means for you.
What this calculator does not include
- Weight and body mass index: the BAI is designed to work without weight.
- Waist circumference, which some studies link more closely with metabolic and heart risk than the BAI does.
- Children: the study covered adults, so the index is not meant for children.
Worked example: height 165 cm, hip 95 cm
Height in metres: 165 ÷ 100 = 1.65 m.
Height to the power 1.5: 1.65^1.5 = 2.12.
Hip divided by that: 95 ÷ 2.12 = 44.8.
BAI = 44.8 − 18 = 26.8, so the estimated body fat is about 26.8 percent.
| Step | Result |
|---|---|
| Height in metres | 1.65 m |
| Height to the power 1.5 | 2.12 |
| Hip divided by that | 44.8 |
| Body adiposity index | 26.8 |
Frequently asked questions
What does the body adiposity index measure?
It estimates body fat percentage from hip circumference and height. Its authors designed it to give a value close to percentage body fat without a scale.
Why does the BAI not use weight?
Bergman and colleagues wanted an index that can be used where a scale is not available or accurate. They noted that body mass index is of limited accuracy and differs between men and women with similar body fat (Bergman et al. 2011).
Is a BAI of 26.8 high or low?
This calculator does not say, because the source gives no cut-off values. Compare your result with the ranges in the body fat calculator, and ask your doctor what it means for you.
Is the BAI better than the body mass index?
A 2012 study found that the BAI is not more accurate than body mass index, waist circumference or hip circumference for estimating body fat (Freedman et al. 2012). Each of these measures has its limits.
Does the calculator store my measurements?
No. The calculation runs in your browser and nothing you enter is sent to us.
Sources
- Bergman RN et al. (2011): A better index of body adiposity, Obesity (PubMed)
- Freedman DS et al. (2012): The body adiposity index (hip circumference / height^1.5) is not a more accurate measure of adiposity than is BMI, waist circumference, or hip circumference, Obesity (PubMed)
Figures and text last checked on Tuesday, November 10, 2026.