Calculate your A Body Shape Index (ABSI) and mortality risk z-score from waist circumference, height, and weight. Predicts premature death risk beyond BMI.
The A Body Shape Index (ABSI) Calculator computes your ABSI value and corresponding mortality risk z-score based on waist circumference, height, weight, age, and sex. Unlike BMI, which cannot distinguish between muscle and fat or account for fat distribution, ABSI specifically captures the health hazard associated with abdominal adiposity.
Developed by Krakauer and Krakauer (2012) using NHANES data, ABSI was shown to be a strong predictor of premature mortality independent of BMI. A higher ABSI indicates greater central adiposity relative to what would be expected from BMI and height alone, and is associated with increased risk of cardiovascular disease, diabetes, and all-cause mortality.
This calculator provides your ABSI value, z-score, and a five-tier risk classification from Very Low to Very High, along with complementary metrics including BMI, body surface area, and waist-to-height ratio for a comprehensive anthropometric profile. It is intended as a screening and comparison tool, helping you see how waist size relates to overall body size in a way BMI alone cannot show. Check the example with realistic values before reporting.
BMI alone is a poor measure of health risk because it does not account for where body fat is distributed. Two people with the same BMI can have very different health outcomes depending on whether fat is distributed abdominally or peripherally. ABSI addresses this limitation by incorporating waist circumference in a way that is independent of BMI and height.
Using ABSI alongside BMI gives a more complete picture of metabolic risk and can motivate targeted interventions focusing on reducing visceral fat, which is more metabolically active and dangerous than subcutaneous fat.
ABSI = WC / (BMI^(2/3) × Height^(1/2)) Where: • WC = Waist circumference (meters) • BMI = Weight / Height² (kg/m²) • Height in meters Z-Score = (ABSI − Mean_ABSI) / SD_ABSI Mean ABSI varies by age and sex. Higher z-scores indicate greater mortality risk.
Result: ABSI = 0.07834, Z-score = -0.33, Low Risk
A 45-year-old male with height 175 cm, weight 80 kg, and waist circumference 90 cm has an ABSI of 0.07834 and a z-score of -0.33, placing him in the Low Risk category for premature mortality.
Krakauer and Krakauer developed ABSI in 2012 by analyzing NHANES data to find a measure of waist circumference that was independent of BMI and height. They discovered that WC/(BMI^(2/3) × Height^(1/2)) effectively isolates the mortality risk from abdominal adiposity. In their validation study using over 14,000 participants tracked for 5+ years, ABSI z-score was a significant predictor of all-cause mortality.
ABSI has some limitations: it was derived primarily from US populations, reference values may not perfectly apply to all ethnic groups, and it relies on accurate waist circumference measurement. Additionally, like all anthropometric indices, it cannot directly measure visceral fat — imaging techniques like DEXA or CT scans provide more precise quantification.
Clinicians and public health researchers use ABSI to identify individuals whose BMI classification may underestimate their metabolic risk. A person with normal BMI but high ABSI may benefit from the same lifestyle interventions typically recommended for overweight individuals.
BMI only considers height and weight, while ABSI incorporates waist circumference to capture abdominal fat distribution. ABSI predicts mortality risk independently of BMI, making it a complementary measure.
A z-score below -0.272 is considered low risk. Negative z-scores indicate less abdominal adiposity than average for your age and sex, while positive scores indicate more.
Measure at the level of the navel (umbilicus) while standing, after a normal exhale. Use a flexible tape measure snug against the skin but not compressing it. Measure over bare skin if possible.
ABSI was developed using US NHANES data representing diverse populations. However, like all population-based indices, it may be less accurate for individuals at extreme body compositions or certain ethnic groups.
Yes. Reducing waist circumference through aerobic exercise, dietary changes, stress reduction, and adequate sleep can lower ABSI. Even modest reductions in visceral fat can improve metabolic health markers.
Use both. BMI captures overall body size, while ABSI captures the additional risk from abdominal fat distribution. Together, they provide a more complete picture of health risk than either alone.