Body Adiposity Index (BAI) Calculator - Hip to Height Ratio

Calculate Your BAI

Gender

Height (cm)

Hip Circumference (cm)

💡 Measure around the widest part of your buttocks

Your Results

Body Adiposity Index

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Estimated Body Fat %

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⚠️ Important Note

BAI is less accurate than direct body fat measurement methods like DEXA or skinfold calipers. Use the U.S. Navy Body Fat Calculator for more reliable estimates.

Body Fat Ranges

Men

• Essential: 2-5%
• Athletes: 6-13%
• Fitness: 14-17%
• Average: 18-24%
• Obese: ≥25%

Women

• Essential: 10-13%
• Athletes: 14-20%
• Fitness: 21-24%
• Average: 25-31%
• Obese: ≥32%

How BAI Works

Formula

BAI = (Hip Circumference / Height^1.5) - 18

Key Features

✓ No weight needed - useful when scales unavailable
✓ Hip-based - correlates with gluteal-femoral fat
✓ Quick estimate - requires only 2 measurements
✗ Less accurate - than DEXA, BIA, or Navy method
✗ Population specific - validated primarily on Mexican-Americans

Limitations

• May overestimate body fat in athletes with muscular hips
• Accuracy varies across different ethnic groups
• Not validated for children or pregnant women
• Hip measurement technique affects results significantly

Measuring Hip Circumference

1

Stand with feet together, relax your muscles

2

Locate the widest part of your buttocks when viewed from the side

3

Wrap tape measure around hips parallel to the floor

4

Tape should be snug but not compressing the skin

5

Take measurement at the end of a normal breath

FAQs

Is BAI more accurate than BMI?

Not necessarily. While BAI attempts to estimate body fat directly, it's less accurate than the U.S. Navy method or bioelectrical impedance. Use BAI only when weight measurement is impractical.

Why doesn't BAI need weight?

BAI uses hip circumference as a proxy for body fat, since fat tends to accumulate in the hip/gluteal area. The formula was developed to correlate hip-to-height ratio with body fat percentage measured by DEXA scans.

Should athletes use BAI?

No. BAI tends to overestimate body fat in athletes with muscular hips and thighs. Use skinfold calipers, DEXA, or the Navy method instead.

How often should I measure BAI?

Check every 4-8 weeks if tracking body composition changes. Hip circumference changes slowly, so more frequent measurements aren't useful.

References

📚

Bergman RN, et al. (2011) - A better index of body adiposity

Original BAI study published in Obesity

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Freedman DS, et al. (2012) - Relation of BAI and BMI to Body Fat

CDC study comparing BAI accuracy