Calculadora do Índice de Arredondamento Corporal (BRI)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
BRI = 364,2 − 365,5 × √(1 − (cintura/(π·altura))²)
About this calculator
The Body Roundness Index (BRI) calculator estimates body shape based on waist circumference and height. Unlike BMI, which uses only weight and height, BRI considers abdominal fat distribution. The formula is: BRI = 364.2 - 365.5 × √(1 - (waist/(π·height))²). The result is a dimensionless number, usually between 1 and 16.
To use the calculator, measure your waist at navel level and your height in meters. Enter the values and click Calculate. The BRI indicates body roundness: low values (1-3) suggest a more elongated body; high values (above 5) indicate greater abdominal fat. Values between 3 and 5 are typical for healthy adults.
BRI is useful for assessing health risks associated with central obesity, such as cardiovascular disease and type 2 diabetes. Health professionals may use it as a complement to BMI. However, BRI does not replace a complete medical evaluation. It is more accurate than BMI for estimating visceral fat but still depends on measurement quality.
Cautions: measure the waist without compressing the skin and after normal exhalation. Height should be measured without shoes. BRI is not suitable for children, pregnant women, or people with high muscle mass. Small measurement errors can significantly affect the result. Use the calculator as a reference, not a diagnosis.
Frequently asked questions
What is the difference between BRI and BMI?
BMI uses only weight and height, while BRI considers waist circumference to estimate abdominal fat distribution. BRI may be more indicative of health risks related to central obesity.
What does a very high BRI mean?
A high BRI (above 5) suggests greater body roundness and possible visceral fat accumulation, which is associated with higher risk of cardiometabolic diseases.
How to measure waist correctly?
Use a flexible tape measure at navel level, without compressing the skin. Measure after normal exhalation, keeping the tape parallel to the floor.
Does BRI work for athletes or muscular people?
BRI may overestimate body fat in people with high muscle mass, as the formula does not distinguish fat from muscle. Interpret the result with caution in such cases.
Can BRI replace medical exams?
No. BRI is a screening tool, but it does not replace clinical exams or imaging for assessing body composition or health risks.