Body Roundness Index (BRI) Calculator
Estimate your body shape and visceral fat risk from your waist and height with the Body Roundness Index.
Body CompositionScience-backed formula
Enter your details
Fill in the fields, then calculate
Enter your waist.
Enter your height.
Awaiting Data
Enter your details and tap Calculate to see your results appear here.
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ResultYour result appears here.
What it measures
The Body Roundness Index turns your waist and height into a single shape score. It tracks central fat better than BMI, since it focuses on the waistline.
Your measurements become one clear number you can track over time.
Higher scores point to a rounder shape and more visceral fat, which links to heart and metabolic risk.
How to use this calculator
- Choose metric or US units.
- Measure your waist at the navel and enter it.
- Enter your height.
- Tap Calculate for your BRI.
The formula used
BRI = 364.2 − 365.5 × √(1 − ((waist / 2π)² / (0.5 × height)²))
- waist
- Waist circumference.
- height
- Standing height, same units as waist.
Understanding Your Results
Lean shape
BRI under 3.5
Lower central fat.
Average
3.5 to 5.5
A typical adult range.
Elevated
5.5 to 6.9
More central fat.
High
BRI above 6.9
Higher visceral fat risk.
Tips to Improve
- Trim waistline fat with a calorie deficit.
- Add strength and cardio training.
- Limit refined carbs and alcohol.
- Re-measure monthly.
Frequently Asked Questions
It captures central fat that BMI misses, so the two work well together.
Measure around the navel, relaxed, after a normal breath.
Most healthy adults fall under about 5.5, though context matters.
Scientific References
- Thomas, D. M., et al. (2013). Relationships between body roundness with body fat. Obesity, 21(11), 2264–2271.
- Rico-Martín, S., et al. (2020). Effectiveness of body roundness index. Obesity Reviews, 21(7), e13023.