A Body Shape Index (ABSI) Calculator

Inputs

Units:
Metric (cm, kg)
Gender
Years (15–90)
cm
kg
cm

Measure midway between the lowest rib and top of the iliac crest.

Your body shape metrics

ABSI

0.0783 Average · z -0.32

BMI

23.5 Normal range

Waist/Height

48.6% Low central risk
ABSI band
z-score range
COMPARISON TO POPULATION
Very low
< -1.0
Well below the population average
Below average
-1.0 to -0.5
Slightly below the population average
Average
-0.5 to 0.5
Comparable to the NHANES reference average
Above average
0.5 to 1.0
Above the population average
High
> 1.0
Well above the population average

BMI-adjusted waist

10.4 cm
Waist ÷ BMI 2/3

Waist target (0.5 × height)

87.5 cm
-2.5 cm vs current

Lean mass estimate

55.6 kg
weight x (1 - body fat % / 100)

Sources

  • Krakauer NY, Krakauer JC. A new body shape index predicts mortality hazard independently of body mass index. PLoS ONE. 2012;7(7):e39504. PMID 22815707 · doi:10.1371/journal.pone.0039504 — original ABSI formula, derived from NHANES 1999–2004 data.
  • Krakauer NY, Krakauer JC. Dynamic association of mortality hazard with body shape. PLoS ONE. 2014;9(2):e88793. PMID 24586405 · doi:10.1371/journal.pone.0088793 — population z-score reference values.
  • Centers for Disease Control and Prevention (CDC). National Health and Nutrition Examination Survey (NHANES). cdc.gov/nchs/nhanes — reference population dataset used for age- and sex-specific norms.

A Body Shape Index (ABSI) is a metric that describes how waist circumference relates to height and weight. It was introduced by Krakauer & Krakauer in 2012 as a way to express body shape using a value that is largely independent of Body Mass Index (BMI), so it conveys information about waist size that BMI alone does not capture. Two people with the same BMI can have different ABSI values depending on how their measurements compare.

To use the calculator, enter age, sex, height, weight, and waist circumference. The tool returns your ABSI value, your BMI, your waist-to-height ratio, and a z-score that places your ABSI relative to population reference values from the U.S. NHANES dataset for your age and sex.

How it works (formula)

  • BMI = weight (kg) ÷ height (m)²
  • Waist-to-height ratio = waist ÷ height
  • ABSI = waist (m) ÷ ( BMI 2/3 × height (m) 1/2 )
  • Z-score compares your ABSI to age- and sex-specific NHANES reference means and standard deviations.

In the original research, ABSI was constructed to have little correlation with height, weight, or BMI. In the population studied by Krakauer & Krakauer, higher ABSI values were statistically associated with higher mortality hazard across the cohort, independently of BMI. These are population-level associations from observational data and describe groups, not individuals.

All outputs are general estimates for informational and educational purposes and represent a statistical comparison to a reference population, not an assessment of any individual's health.