Body Adiposity Index CalculatorFree online fitness & health calculator — instant results, no sign-up
Estimate adult body adiposity from hip circumference and height.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Body Adiposity Index Calculator
The Body Adiposity Index Calculator estimates adult body adiposity from hip circumference and height, without requiring body weight. It uses the Body Adiposity Index (BAI) formula to produce an approximate body fat percentage. The result is an educational estimate, not a direct measurement of body fat or a diagnosis.
- Hip circumference (cm)
- Enter the circumference around the widest part of your buttocks in centimeters; the default is 100 cm.
- Height (cm)
- Enter your standing height without shoes in centimeters; the default is 175 cm.
Formula and method
h = H / 100; BAI = C / h^1.5 − 18. With the default inputs: BAI = 100 / (175 / 100)^1.5 − 18 ≈ 25.2%.
- CHip circumference in centimeters.
- HHeight entered in centimeters.
- hHeight converted to meters.
- BAIBody Adiposity Index, expressed here as an estimated body fat percentage.
Convert height from centimeters to meters, raise the height in meters to the power of 1.5, divide hip circumference in centimeters by that value, and subtract 18. Round the result to one decimal place for display. The formula is unit-specific: hip circumference must remain in centimeters while height must be in meters.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Hip circumference100 cm
- Height175 cm
Results
- Estimated body adiposity25.2 %
- NoteEducational estimate for adults; not a diagnosis or treatment recommendation.
How to use the Body Adiposity Index Calculator
- 1Measure around the widest part of your buttocks with a flexible tape, keeping it level and snug without compressing the skin.
- 2Enter that measurement under Hip circumference (cm); the default is 100.
- 3Measure your standing height without shoes and enter it under Height (cm); the default is 175.
- 4Run the calculation to obtain the estimated body adiposity.
- 5Read the estimate together with its educational-use note; the default inputs produce 25.2%.
Reading your result
The “Estimated body adiposity” row reports the BAI-based approximation of body fat percentage. With hip circumference of 100 cm and height of 175 cm, it displays 25.2%; this does not establish that your actual body fat percentage is exactly 25.2%. The “Note” row states: “Educational estimate for adults; not a diagnosis or treatment recommendation.” The calculator does not assign a health-risk category or a target body fat percentage.
Limitations
BAI is an indirect, population-derived estimate, and its accuracy varies with sex, age, ethnicity, muscularity, and body fat level. This formula does not directly account for those factors or distinguish fat from muscle and other tissues contributing to hip size. Measurement error can affect the result, and the displayed decimal does not imply equivalent accuracy. It is intended for adults, not children, and should not be relied on during pregnancy or when body proportions are substantially altered. It does not measure abdominal fat distribution and cannot replace a clinical assessment or a validated body composition measurement.
Common questions
Should I measure my waist or my hips for BAI?+
Measure your hips around the widest part of your buttocks, not your waist. Substituting waist circumference changes the meaning of the input and does not produce the intended BAI estimate.
Why does this calculator not ask for my weight?+
BAI uses only hip circumference and height. Unlike BMI, which uses weight and height, BAI was designed as a body adiposity estimate without a weight input.
Should I enter my height as 175 or 1.75?+
Enter 175 because the height input uses centimeters. The calculator converts this to 1.75 meters before applying the BAI formula.
Does the default result of 25.2% mean my body fat is healthy?+
No. The result is an estimate rather than a health classification, and interpretation depends on factors this calculator does not collect, including age, sex, and medical context.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.