Body composition

A Body Shape Index calculator

Calculate ABSI and compare it with the original age- and sex-specific reference data.

Free · No account neededMethod & sources

YOUR INPUTS

Your measurements

Measurement units

Use the sex category specified by the source equation.

The original NHANES protocol measured waist at the upper border of the iliac crest.

Inputs stay in this browser.

YOUR RESULT

Start with your numbers.

Complete the fields to see the calculation, method, and limits.

UNDERSTAND THE METHOD

How to use this calculator

Enter height, weight, waist, and age. ABSI adjusts waist for height and weight. The z-score expresses the distance from the original age- and sex-specific reference mean in standard deviations. This tool uses completed whole years and the smoothed Table S1 data.

What the result can tell you

ABSI is a screening index, not a diagnosis or lifespan estimate. The original mortality study included adults aged 18 and older. Study hazard ratios describe groups and do not predict an individual chance of death. The original source does not provide the continuous mortality curve used by some calculators.

Common questions

What measurements does ABSI use?

Enter height, weight, waist, and age. ABSI adjusts waist for height and weight, then compares the result with the age- and sex-specific reference data.

Does ABSI predict my lifespan?

No. ABSI is a screening index. The source hazard ratios describe groups and do not predict an individual lifespan or chance of death.

Sources & limitations

Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.

  1. Krakauer and Krakauer define ABSI and publish population study comparisons.journals.plos.org
  2. Original Table S1 provides age- and sex-specific smoothed reference means and standard deviations.journals.plos.org
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