BRI Calculator
Calculate Body Roundness Index (BRI), a modern measure of central adiposity that combines waist circumference and height.
What is BRI?
Body Roundness Index (Thomas et al., 2013) treats the body as an ellipse and computes its eccentricity from waist and height. Lower BRI indicates a leaner, more elongated body shape; higher BRI indicates a rounder, more central-adiposity-heavy shape. Recent studies link high BRI with increased mortality and metabolic disease.
How is it calculated?
BRI = 364.2 − 365.5 × √(1 − (waist / (2π))² / (0.5 × height)²), with both circumferences in metres. Population studies suggest BRI < 3.4 = lean, 3.4–6.9 = healthy, ≥ 6.9 = elevated cardiometabolic risk.
Frequently Asked Questions
- Why use BRI over BMI?
- BRI directly captures abdominal fat distribution, which BMI cannot.
- Is BRI age-adjusted?
- No, but health risk thresholds may shift with age.
- How do I measure waist for BRI?
- At the umbilicus, gently snug, after exhaling normally.