📏ABSI Calculator
Calculate your A Body Shape Index (ABSI) to assess health risks based on waist circumference, height, and BMI
Last updated: November 7, 2025
The 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
- Waist circumference
If you are interested in the more known BMI, visit our BMI calculator: with a few inputs and no time at all, you will be able to calculate its value!
A Body Shape Index Formula - ABSI Formula and ABSI Z Score
We present the ABSI formula below:
ABSI = WC ÷ (BMI2/3 × Height1/2)
where:
- WC: The waist circumference, expressed in meters
- Height: Expressed in meters
- BMI: Expressed in kg/m², and is calculated using: BMI = weight ÷ height²
To estimate the risk of premature mortality, we can calculate the ABSI z score as follows:
ABSI z score = (ABSI - ABSImean) ÷ ABSISD
where:
- 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
- ABSISD: The standard deviation of the calculated ABSI for the chosen age and sex
This calculator uses the 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 to -0.272 | Low |
| -0.272 to +0.229 | Average |
| +0.229 to 0.798 | High |
| > 0.798 | Very high |
Our BAI calculator will explain to you another index used to calculate your fitness: the body adiposity index.
How to Use A Body Shape Index (ABSI) Calculator?
Using the ABSI calculator is very easy: just follow these steps:
- Choose your sex.
- Enter your age (the values must range from 2 to 85 years).
- Enter your height. Don't worry about the units, as our ABSI calculator has a built-in length converter.
- Enter your weight. Again, don't worry about the units conversion.
- 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 the ABSI score is based only on the body model. Other factors that influence life expectancy (e.g., other illnesses) are not taken into account. We created our diabetes risk calculator and CVD risk calculator to give you a more comprehensive model to calculate those risks.
We try our best to make our calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. If any health condition bothers you, consult a physician.
Frequently Asked Questions
ABSI (A Body Shape Index) is a metric that combines waist circumference, height, and BMI to assess health risks and mortality risk. It was developed to better predict health outcomes than BMI alone by accounting for body shape and fat distribution.
ABSI is calculated using the formula: ABSI = Waist Circumference (m) / (BMI^(2/3) × Height^(1/2)). You need your waist circumference in centimeters, height in centimeters, and weight in kilograms to calculate it.
ABSI values typically range from 0.06 to 0.10. Lower ABSI values generally indicate lower health risk. A Z-score below 0 suggests below-average risk, while a Z-score above 1 suggests elevated risk. However, interpretation should consider age, gender, and other factors.
To measure waist circumference: Stand straight and breathe out. Wrap a measuring tape around your waist at the level of your navel (belly button). Make sure the tape is parallel to the floor and snug but not compressing your skin. Read the measurement in centimeters.
While BMI only considers height and weight, ABSI incorporates waist circumference, which provides information about fat distribution. ABSI can better predict health risks because abdominal fat (visceral fat) is more strongly associated with health problems than overall body fat.
The ABSI Z-Score compares your ABSI value to the population average. A Z-score of 0 means your ABSI is at the population average. Negative Z-scores indicate lower risk, while positive Z-scores indicate higher risk. Z-scores above 1 or 2 suggest significantly elevated risk.