A Body Shape Index (ABSI) Calculator
Calculate the original raw ABSI from height, weight, and waist with explicit raw-versus-z-score and measurement limits.
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About
A Body Shape Index (ABSI) scales waist circumference by BMI and height. The original 2012 derivation analyzed 14,105 nonpregnant US adults aged 18 years or older in NHANES 1999–2004; it proposed a research index, not a direct measurement of visceral fat or an individual diagnosis. [1]
This page calculates only the original raw ABSI. Age and sex do not enter that raw equation. An ABSI z-score is a separate standardization requiring age, sex, and a defined reference population’s mean and standard deviation; no z-score, percentile, mortality category, or personal probability is produced here. [1, 2]
Formula
Interpretation
Raw ABSI is not an ABSI z-score
| Quantity | What it needs | What this page does |
|---|---|---|
| Raw ABSI | Height, weight, waist | Calculated and displayed neutrally |
| ABSI z-score | Raw ABSI plus age-, sex-, and population-specific mean and SD | Not calculated |
| Mortality association | Defined cohort, endpoint, follow-up, standardization, and adjusted statistical model | No personal risk estimate or category |
The 2012 NHANES analysis and 2014 British cohort used reference distributions and population-level models. Their associations do not convert one raw value into an individualized probability. [1, 2]
What later research found—and why it is not a universal lookup table
European cohort research and a meta-analysis of prospective studies reported population-level associations between ABSI or central-fatness indices and mortality. However, effect size, standardization, population, outcome, and adjustment varied, with substantial heterogeneity in pooled estimates. A 15-year study of 780 middle-aged Chinese men did not find an association between ABSI and mortality. These results support careful research use, not a universal raw-value cutoff or an automatic personal mortality label. [3, 4, 5]
Waist measurement protocol matters
The NHANES protocol marks the uppermost lateral border of the ilium and measures waist circumference in a horizontal plane at that level. WHO describes a midpoint between the lowest palpable rib and the top of the iliac crest. The iliac-crest site, midpoint, navel, and narrowest waist are not interchangeable. Keep the site, posture, breathing phase, clothing, and tape tension consistent when comparing repeated measurements. This page cannot identify which protocol produced an entered number. [6, 7]
ABSI compared with other anthropometric measures
| Measure | Inputs | Output | Why it is not interchangeable |
|---|---|---|---|
| Raw ABSI | Waist, weight, height | Waist scaled by BMI and height | Not an age/sex z-score or direct fat measure |
| BMI | Weight, height | Weight-height index | Does not include waist distribution |
| Waist circumference | Waist | External circumference | Not scaled for BMI and height |
| WHtR | Waist, height | Simple ratio | Does not use weight or BMI |
| WHR | Waist, hip | Distribution ratio | Uses hip circumference as denominator |
| BRI | Waist, height | Thomas geometric mapping | Different formula and model target |
| RFM | Waist, height, published sex variable | Regression body-fat estimate | Different input and estimated outcome |
Situations outside a simple raw-index interpretation
The original derivation population was nonpregnant US adults aged 18 years or older. Children, pregnancy, ascites, edema, marked abdominal distension, abdominal masses, amputation, inability to stand consistently, unusual body shape or composition, and changes in waist site can reduce comparability or represent extrapolation. The calculator cannot detect those contexts and provides no diagnosis, health classification, treatment target, diet, exercise plan, medication, or personal mortality probability. [1, 6, 7]
Worked arithmetic examples
Metric: Height 170 cm, weight 70 kg, and waist 85 cm produce BMI about 24.22 kg/m² and raw ABSI about 0.07787.
Exact US equivalence: 170 ÷ 2.54 inches, 70 ÷ 0.45359237 pounds, and 85 ÷ 2.54 inches produce the same raw values after exact unit normalization. [8]
Larger waist: At the same 170 cm and 70 kg, changing waist from 85 to 95 cm increases the raw ABSI because waist is the equation numerator. This is arithmetic, not a diagnosis or risk category.
Blank, zero, negative, exponent-form, nonnumeric, nonfinite, or unsafe values produce no result. Scientific notation is deliberately rejected so the complete submitted decimal is unambiguous.
References
- 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. PMCID PMC3399847. doi:10.1371/journal.pone.0039504.
- Krakauer NY, Krakauer JC. Dynamic association of mortality hazard with body shape. PLoS One. 2014;9(2):e88793. PMID 24586394. PMCID PMC3930607. doi:10.1371/journal.pone.0088793.
- Christakoudi S, et al. A Body Shape Index (ABSI) achieves better mortality risk stratification than alternative indices of abdominal obesity: results from a large European cohort. Sci Rep. 2020;10(1):14541. PMID 32883969. PMCID PMC7471961. doi:10.1038/s41598-020-71302-5.
- Jayedi A, Soltani S, Zargar MS, Khan TA, Shab-Bidar S. Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies. BMJ. 2020;370:m3324. PMID 32967840. PMCID PMC7509947. doi:10.1136/bmj.m3324.
- He S, Zheng Y, Wang H, Chen X. Assessing the relationship between a body shape index and mortality in a group of middle-aged men. Clin Nutr. 2017;36(5):1355–1359. PMID 27663543. doi:10.1016/j.clnu.2016.09.003.
- CDC/NCHS. National Health and Nutrition Examination Survey: 2021 Anthropometry Procedures Manual.
- World Health Organization. Waist Circumference and Waist-Hip Ratio: Report of a WHO Expert Consultation. Geneva, 8–11 December 2008. Published 2011. ISBN 9789241501491.
- National Institute of Standards and Technology. The International System of Units (SI): Conversion Factors for General Use, NIST Special Publication 1038. 2006.
FAQ
First calculate BMI as weight in kilograms divided by height in meters squared. Raw ABSI is waist circumference in meters divided by BMI to the two-thirds power and height in meters to the one-half power. This calculator keeps full precision and reports the raw index to five decimal places.
Sources: [1]
No. Raw ABSI uses waist circumference, BMI, and height. Age and sex are used only in separate reference-distribution standardization, so this raw calculator does not ask for or infer them.
Sources: [1]
No. Several cohorts and a meta-analysis reported population-level associations, but estimates varied and pooled analyses showed heterogeneity. A 15-year study of middle-aged Chinese men did not find a mortality association, illustrating why one universal raw-value lookup is not justified.
No. Raw ABSI is an anthropometric equation based on external measurements. It is not CT, MRI, DXA, or another direct body-composition measurement and does not report visceral-fat volume or body-fat percentage.
Sources: [1]
BMI is an intermediate term in the raw ABSI denominator. It is shown only so the equation can be audited; this page does not apply a BMI classification or turn that intermediate value into a diagnosis.
Sources: [1]
Each uses different inputs, scaling, or model targets. Raw ABSI scales waist by BMI and height; BMI omits waist; WHtR is a simple waist-height ratio; WHR uses hip circumference; BRI is a geometric mapping; and RFM is a regression estimate of body fat.
Sources: [1]
No. The original derivation used nonpregnant US adults aged 18 years or older. Pediatric and pregnancy use would be extrapolation and requires separate evidence and context.
Sources: [1]
No. This page performs measurement arithmetic only. It does not prescribe nutrition, activity, weight-loss targets, medication, referral, monitoring, or treatment.
Sources: [1]
Related Calculators
WHtR
Calculate WHtR from waist circumference and standing height in centimeters or inches, with NICE applicability and measurement limits.
Body Roundness Index
Calculate the Thomas 2013 geometric Body Roundness Index from height and waist circumference in centimeters or inches, with measurement and interpretation limits.
BMI
Calculate adult BMI from metric or US customary inputs and view the CDC adult screening category with non-diagnostic interpretation limits.
Disclaimer
Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.