Body shape measurement
Uses height and waist circumference to calculate body roundness.
Free body measurement tool
BRI Calculator
Calculate your Body Roundness Index using your height and waist circumference. Get your BRI score, waist-to-height ratio and clear calculation steps in seconds.
Metric and imperial
No weight required
Instant calculation
Waist
Measure body roundness
BRI uses the relationship between height and waist circumference to describe body shape geometrically.
Enter your measurements
Choose your preferred unit system and add two measurements.
Your results
Review your calculated body measurement values.
Your BRI score
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Lower
Mid
Higher
Height
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Waist
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Waist-to-height ratio
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Eccentricity
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Body roundness context
Calculate your score
Enter your measurements to view a general descriptive context.
Calculation steps
- Enter your height and waist circumference.
- Click Calculate BRI to view the result.
About the tool
What is a BRI calculator?
A BRI calculator finds your Body Roundness Index using height and waist circumference. Unlike calculations that require body weight, BRI focuses on the geometric relationship between your height and waist measurement.
No weight needed
The main BRI calculation does not require your body weight.
Flexible units
Calculate using centimeters or feet and inches.
How it works
How to use the BRI calculator
Only two measurements are needed. The calculator converts your values into a consistent unit and applies the Body Roundness Index formula.
Choose your units
Select metric for centimeters or imperial for feet and inches.
Enter your height
Add your full standing height using your selected measurement system.
Enter your waist size
Measure your waist circumference and enter the value.
View your BRI
Get your BRI score, ratio and calculation steps instantly.
Formula
BRI calculation formula
The formula models body shape geometrically using waist circumference and height in the same unit.
Body Roundness Index formula
BRI = 364.2 − 365.5 × √(1 − (Waist ÷ (π × Height))²)
Step 1
Divide waist circumference by height.
Step 2
Use the ratio to calculate body eccentricity.
Step 3
Apply the final BRI equation to get the score.
Health information notice
This calculator provides a mathematical estimate for general information only. It is not a diagnosis and should not replace advice from a qualified healthcare professional.
FAQ
Frequently asked questions
Common questions about Body Roundness Index and the BRI calculator.
What does BRI stand for?
BRI stands for Body Roundness Index. It is a geometric calculation based on height and waist circumference.
What measurements are needed for BRI?
You need only your height and waist circumference. Body weight is not required for the main BRI calculation.
Can I calculate BRI using inches?
Yes. Select Imperial and enter your height in feet and inches and your waist circumference in inches.
Can I calculate BRI using centimeters?
Yes. Select Metric and enter both your height and waist circumference in centimeters.
Is BRI the same as BMI?
No. The calculations use different measurements. BRI uses height and waist circumference, while BMI uses height and body weight.
Is the BRI calculator a medical diagnosis?
No. The result is a mathematical estimate for general information and should not be treated as a medical diagnosis.