Waist circumference
ABSI z-score

ABSI calculator estimates the risk of premature mortality based on the A Body Shape Index (ABSI). The ABSI formula requires only a few variables: age, sex, body height, body mass, and waist circumference.

The inclusion of the last measurement makes ABSI a better indicator of risk of mortality from excessive weight than the standard body mass index (BMI). Read the article below to find out more about the A Body Shape Index pros and cons and the ABSI formula! 🤓

A Body Shape Index (ABSI)

The A Body Shape Index has been developed by Nir and Jesse Krakauer from a sample of Americans in the National Health and Nutrition Examination Survey. The aim of the authors was to develop a formula that is based on waist circumference and is approximately independent (less dependent) of height, weight, and BMI. They have developed the A Body Shape Index that includes five variables:

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

A Body Shape Index formula - ABSI formula and ABSI z score:

  1. We present the ABSI formula below:
ABSI = WC/ (BMI2/3 * height1/2)


  • 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.

  1. To estimate the risk of premature mortality, we can calculate the ABSI z score as follows:
ABSI z score = (ABSI - ABSImean) / ABSISD


  • ABSI z score - calculated based on the mean and standard deviations of ABSI calculated for the given age and sex;

  • ABSImean - the mean ABSI for the chosen age and sex; and

  • ABSIsᴅ - the standard deviation of the calculated ABSI for the chosen age and sex.

This calculator uses the gets its mean and standard deviation data for each age and sex bracket from the data available for the population of NHANES.

Based on the ABSI z score, the results are classified into five premature mortality risk levels:

ABSI z score
Mortality risk
< -0.868
Very low
-0.868 and -0.272
-0.272 and +0.229
0.229 and 0.798
Very high

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

Using ABSI 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 worry about the units - our ABSI calculator has a built-in length converter.
  4. Enter your weight. Again, don't worry about the units conversion.
  5. Input your waist circumference. It should be measured horizontally around the waist, at the level of your belly button.

That's all! In the "Results" section, you will be able to see your ABSI score, ABSI z score, and the interpretation of your result.

A Body Shape Index - pros and cons

The higher the ABSI, the higher the proportion of abdominal fat compared to other body parts. ABSI correlates only slightly with height, weight, and BMI, indicating that it is independent of other anthropometric variables in predicting mortality. It can also predict the risk of cardiovascular disease, cancer, and diabetes. However, the risk calculated with ABSI score is based only on the body model. Other factors that influence life expectancy (e.g. other illnesses) are not taken into account.

If you are interested in different anthropometric parameters than ABSI and BMI, check the waist-hip ratio, waist to height ratio, body adiposity index, ideal weight, and ponderal index calculators.

Joanna Michałowska, PhD candidate