BRI Calculator
The Body Roundness Index (BRI) estimates how 'round' your body is using your height and waist circumference, giving a single number linked to visceral fat and metabolic risk. Enter your measurements to see your BRI, category, and waist-to-height ratio.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
- The ellipse body model is a mathematical approximation.
- Valid for adults; may be less accurate in children or elderly individuals.
Formula
BRI = 364.2 − 365.5 × √(1 − ((WC / (2π))² / (height/2)²))
where WC and height are in metres
- BRI uses the geometry of an ellipse to translate your waist and height into a roundness score, typically between 1 and 15.
- Both waist circumference and height are converted to metres before being placed in the formula.
- Higher BRI values reflect a rounder body shape and tend to track with more visceral (abdominal) fat.
- Suggested bands: about 1–3.41 healthy, 3.41–4.45 overweight, above 4.45 obese — use them as a guide, not a diagnosis.
- BRI is a screening estimate and does not replace assessment by a qualified healthcare professional.
Height 170 cm, waist 80 cm
Inputs
- Height: 170 cm
- Waist Circumference: 80 cm
With a 170 cm height and 80 cm waist, the BRI works out to roughly 3.4 — right at the top of the healthy band — and a waist-to-height ratio just under 0.5.
Frequently asked questions
What is the Body Roundness Index?
It's a measure of body shape based on height and waist circumference. Unlike BMI, it focuses on how round the torso is, which correlates with visceral fat.
How is BRI different from BMI?
BMI uses height and weight, while BRI uses height and waist. BRI can better reflect central fat distribution, a key driver of metabolic risk.
What is a healthy BRI?
Roughly 1 to 3.41 is considered a healthy range. Higher values suggest increasing abdominal fat and associated health risk.
Where do I measure my waist?
Measure at the narrowest point of your torso, usually just above the belly button, with the tape snug but not compressing the skin.
Is BRI a diagnosis?
No. It is a screening estimate. Discuss any concerns about body composition or health risk with your doctor.
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