Body Roundness Index (BRI) Calculator
Calculate your Body Roundness Index (BRI), a measure of body shape based on waist and height that estimates body and visceral fat. Enter your waist and height to see your BRI and how round your body profile is.
- Waist and height entered in centimetres.
Formula
BRI = 364.2 − 365.5 × √(1 − [(waist ÷ 2π) ÷ (0.5 × height)]²)
- BRI models the body as an ellipse, using the ratio of waist circumference to height to gauge how round versus lean the profile is.
- Both waist and height are entered in centimetres and converted to metres internally.
- Most people fall between about 1 and 16; higher values mean a rounder shape and more central fat.
- BRI correlates with body fat and visceral (abdominal) fat, which is linked to metabolic risk.
- It is a screening indicator, not a diagnosis — combine it with other measures and professional advice.
85 cm waist, 170 cm height
Inputs
- Waist: 85 cm
- Height: 170 cm
With an 85 cm waist and 170 cm height, BRI is about 3.9 — an average roundness profile.
Frequently asked questions
What is the Body Roundness Index?
BRI is a measure of body shape based on waist and height that estimates total and visceral body fat from how round your body is.
How is BRI different from BMI?
BMI uses weight and height; BRI uses waist and height, so it better reflects where fat is stored, especially around the abdomen.
What is a healthy BRI?
Lower values generally indicate a leaner profile. There is no single cut-off, so compare against population ranges and trends over time.
Why does waist matter so much?
A larger waist relative to height signals more central fat, which is more strongly associated with metabolic and cardiovascular risk.
How should I measure my waist?
Measure around the narrowest point, usually just above the navel, with the tape snug but not compressing the skin.
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