MasterTool

Body Adiposity Index Calculator

Estimate body fat percentage with the Body Adiposity Index (BAI) from hip circumference and height — no weight needed.

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What this tool does

Estimate body fat percentage with the Body Adiposity Index (BAI) from hip circumference and height — no weight needed. BAI was calibrated against DXA in the original study population and can err substantially in athletes, older adults and other populations. An estimate, not a measurement.

How to use the Body Adiposity Index Calculator

  1. Enter or select hip circumference in in.
  2. Enter or select height in in.
  3. Read the calculated result; change any measurement to compare alternatives.

Formula

BAI = hip(cm) / height(m)^1.5 − 18 (Bergman et al. 2011)
hip
Hip circumference (in, before metric conversion)
height
Height (in, before metric conversion)

BAI was calibrated against DXA in the original study population and can err substantially in athletes, older adults and other populations. An estimate, not a measurement.

Worked example

For body adiposity index calculator, the following measurements illustrate the exact method: Hip circumference: 40; Height: 69.

Inputs

  • Hip circumference40 in
  • Height69 in

Result

  • Estimated body fat via BAI (%)25.79

Results explained

Estimated body fat via BAI (%)
Estimated body fat via BAI (%) from the formula above. BAI was calibrated against DXA in the original study population and can err substantially in athletes, older adults and other populations. An estimate, not a measurement.

Frequently asked questions

BAI (Bergman et al., 2011) estimates body fat percentage from hip circumference and height alone — no scale required: BAI = hip (cm) ÷ height (m)^1.5 − 18.

In its original validation it tracked DXA reasonably at group level, but later studies found meaningful individual error, especially in lean athletes and older adults. Treat it as a rough estimate.

At the widest circumference over the buttocks, standing with feet together, tape level all the way around.

That is its design: hip size relative to height carried enough signal in the study population to estimate adiposity. The trade-off is it cannot detect changes in muscle or visceral fat.

Neither is a direct measurement; each is a regression estimate from a different population. For tracking, pick one method and follow its trend; for a measurement, use DXA or a clinical assessment.