What is A Body Shape Index (ABSI)

ABSI is a metric for assessing the health implications of a given body height, mass and waist circumference. It was developed by Nir and Jesse Krakauer from a sample of Americans in the National Health and Nutrition Examination Survey. It includes five variables:

  • sex;
  • age;
  • weight;
  • height;
  • and waist circumference

A criticism of BMI is that it does not distinguish between muscle and fat mass and may be elevated in people with increased BMI due to muscle development rather than fat accumulation from overeating. A higher muscle mass may actually reduce the risk of premature death. A high ABSI appears to correspond to a higher proportion of central obesity or abdominal fat.

This picture represents death. If we don't pay attention on our body and health we have more chance to fall ill or die from heavy diseases.

A Body Shape Index (ABSI) Formula

The equation for ABSI is based on statistical analysis and is derived from an allometric regression.

ABSI = \frac{WC}{BMI^\frac{2}{3} * height^\frac {1}{2}}

Studies have associated ABSI with total mortality and cardiovascular risk, indicating that it is useful in assessing cardio-metabolic risks.


  • WC – the waist circumference, expressed in m;
  • height – expressed in m; and
  • BMI – expressed in kg / m2 and is calculated using the following formula:
  • BMI = weight / height².

To estimate the risk of premature mortality, we can calculate the ABSI z score as follows:

ABSI_z score = (ABSI – ABSI_{mean}) / ABSI_SD

Based on this score, the results are classified into 5 risk levels of mortality:

ABSI z scoreMortality risk
< -0.868Very low
                      -0.868 and -0.272Low
-0.272 and +0.229Average
0.229 and 0.798High
>0.798Very high

Why ABSI is perhaps better than BMI

In the research, Team Krakauer calculated ABSI and BMI on more than 14,000 Americans of various shapes and sizes and found that a high ABSI score was more accurate than a high BMI score in predicting mortality. Those with a high ABS score had more than double the chance of dying from some disease someone with a low score. And at the same time, their BMI score was within normal limits, but they were in the high limits of the ABSI score and the risk group.

How to use A Body Shape Index (ABSI) calculator?

Using this calculator is very easy – just follow these steps:

  1. Choose your sex.
  2. Enter your age (the values must range from 2 to 85 years).
  3. Enter your height. Don’t bother about the units
  4. Enter your weight. Again, don’t bother about the units.
  5. Input your waist circumference. It should be measured horizontally around the waist, around your belly button.

Be sure to check out our BMI Calculator!