Body Roundness Index (BRI) Calculator
The Body Roundness Index (BRI) is a newer health metric that accounts for body shape — specifically how "round" your body is — rather than just weight relative to height like BMI. Our BRI Calculator computes it instantly.
What Is BRI?
Developed in 2013 by mathematician Diana Thomas, BRI uses waist circumference and height to estimate body shape as an ellipse. Research shows BRI correlates better with visceral fat and cardiometabolic risk than BMI.
BRI = 364.2 − 365.5 × √(1 − ((waist/(π × height))²))
BRI vs BMI
| Metric | What It Measures | Accounts for Body Shape? | Better for |
|---|---|---|---|
| BMI | Weight ÷ height² | No | Population-level screening |
| BRI | Waist + height → body roundness | Yes | Individual health risk |
| WHtR | Waist ÷ height | Partially | Central adiposity |
BRI Health Risk Categories
| BRI Range | Health Risk |
|---|---|
| < 3.4 | Very low (underweight risk) |
| 3.4 – 5.2 | Low (healthy) |
| 5.3 – 6.9 | Moderate |
| 7.0 – 8.5 | High |
| > 8.5 | Very high |
Why BRI Matters
BMI misses "normal weight obesity" — people with normal BMI but high body fat, especially visceral fat around the waist. BRI catches this because it directly incorporates waist circumference.
Also check your WHtR → Calculate your BMI →