Comprehensive Calculator Guide
The body adiposity index (BAI) estimates body fat from just two measurements, hip circumference and height, with no scales. A man 178 cm tall with a 100 cm hip comes out at 24.1%, in the overweight band for ages 20–39. The calculator compares your result with the healthy range for your age and sex, since women’s ranges are higher and both rise with age.
Origin, accuracy and ranges
Richard Bergman and colleagues published BAI in 2011, built on DEXA body-fat data: hip (cm) ÷ height (m)^1.5 − 18. Later studies found its accuracy about the same as BMI’s, with errors that differ by sex and fat level, so it suits tracking yourself over time.
Healthy ranges (Gallagher et al.): men 8–21% at 20–39, 11–23% at 40–59, 13–25% at 60–79; women 21–33%, 23–35% and 24–36%.
How to Use
- Choose your sex and age group.
- Enter your hip circumference at the widest point, then your height.
- Press “Calculate BAI” to see your estimated body fat, its band and your healthy range.
Formula Used
BAI = hip (cm) ÷ height (m)^1.5 − 18
Practical Examples
- Example 1
- Man 20–39, hip 100 cm, 178 cm: 24.1%, overweight.
- Example 2
- Woman 40–59, hip 105 cm, 162 cm: 32.9%, healthy.
Important Tips
- Measure standing, feet together, tape level and not pulled tight.
Common Mistakes to Avoid
- Measuring at the hip bone instead of the widest point of the buttocks.
Frequently Asked Questions
- How do I estimate body fat from hip and height?
- Hip in cm ÷ height in m to the power 1.5, minus 18.
- Is BAI accurate?
- About as accurate as BMI; it’s an estimate, not a measurement.
- What is a healthy body fat for women?
- About 21–33% at ages 20–39, a little higher with age.