Body Roundness Index (BRI) Calculator - Body Shape from Height and Waist
Body Roundness Index Calculator
How round is your body shape?
Shape, Not Just Weight
BRI models the body as an ellipse. A narrow, tall ellipse scores low, and a rounder one scores higher.
Two Measurements
Only height and waist are needed. No scale, no body-fat device.
Linked to Health Risk
Studies have linked higher BRI to more visceral fat and a higher risk of metabolic and heart conditions.
Private
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What the Body Roundness Index Tells You
The Body Roundness Index was proposed in 2013 by Diana Thomas and colleagues as a better way to describe body shape than the body mass index. It treats the body as an ellipse whose height is your height and whose width is worked out from your waist circumference, then converts how far the ellipse is from a perfect circle into a number. The formula is 364.2 minus 365.5 times the square root of one minus the squared ratio of the ellipse’s half-width to its half-height.
Researchers use BRI because the waist carries information that weight and BMI miss: two people with the same BMI can have very different amounts of fat around the organs. There is no single official set of cut-offs for individuals, so treat the number as a way to compare yourself with your earlier self and to follow the effect of lifestyle changes, rather than as a diagnosis.
Key Takeaways
- A trend tool: Measure the same way each time and watch the direction of change.
- Adults only: The index was developed for adults.
- Related calculators: See also the Waist-to-Height Ratio Calculator and the Body Fat Calculator.