ABSI Calculator

A Body Shape Index, abbreviated ABSI, is an anthropometric measure designed to describe waist size relative to a person's height and weight. Body mass index uses weight and height but does not directly represent fat distribution. Waist circumference adds information about central body shape, which is associated at a population level with cardiometabolic risk. ABSI combines all three measurements in a way intended to be less correlated with BMI than waist circumference alone. The formula uses waist circumference in meters divided by BMI raised to the power of two-thirds and height in meters raised to the power of one-half. BMI is weight in kilograms divided by height in meters squared. As an example, a waist of 85 centimeters, weight of 70 kilograms, and height of 175 centimeters gives a BMI of about 22.9 and an ABSI of about 0.0798. The ABSI number is small because waist is expressed in meters and divided by scaled terms. An unstandardized ABSI value does not have one universal low, average, or high cutoff. Research commonly converts the raw value to an age- and sex-specific z-score using population means and standard deviations. Different reference datasets can produce different percentiles or risk estimates. This calculator deliberately reports the raw ABSI and BMI rather than claiming a mortality category without the necessary demographic reference table. It is best suited to transparent calculation, research comparison, or tracking measurements taken under consistent conditions. Measure waist at the anatomical site required by the chosen protocol, usually after a normal exhalation, with the tape horizontal and snug but not compressing skin. Protocols differ on whether the site is the midpoint between the lowest rib and iliac crest, the top of the iliac crest, or another landmark. Height and weight should also be measured accurately. ABSI does not distinguish muscle from fat, diagnose visceral fat, or account for pregnancy, edema, unusual body proportions, or changes caused by illness. No body index should be used alone to predict an individual's health outcome. Discuss concerns about waist size, weight, blood pressure, glucose, lipids, or cardiovascular risk with a qualified healthcare professional who can interpret the complete health picture.