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Conicity Index Calculator

Estimate central (abdominal) fat distribution from waist circumference, weight, and height using Valdez's conicity index, in metric or imperial units.

Conicity index
1.215

How it works

Valdez's conicity index (1991) models your torso as somewhere between a plain cylinder and two cones joined base-to-base at the waist: C = waist circumference(m) ÷ (0.109 × √(weight(kg) ÷ height(m))). A value close to 1 reads as a cylindrical shape with fat spread evenly along the torso; higher values, up toward the index's practical ceiling around 1.7–1.9, reflect fat concentrated more centrally around the abdomen — the two-cones shape the index is named for.

The 0.109 constant is a fixed geometric conversion factor from the original paper (not a lookup value that changes), so the formula is applied identically regardless of your inputs. Because it mixes three differently-dimensioned quantities — a length, a mass, and another length under a square root — metric inputs are converted to canonical meters and kilograms before the formula runs, the same convert-to-canonical-then-back approach the U.S. Navy body fat formula uses internally, rather than relying on the ratio alone to cancel units.

Unlike waist-to-hip or waist-to-height ratio, the conicity index folds in overall body weight as well, which is why it needs the weight/height mixed-unit conversion those simpler ratio calculators don't.

FAQ

What counts as a 'high' conicity index?

Published cutoffs vary by study population and aren't as universally standardized as, say, BMI's categories — commonly cited references put the healthy range roughly under 1.25 for men and 1.18 for women, with higher values associated with greater cardiometabolic risk, but there's no single agreed-upon threshold the way there is for waist-to-hip ratio's WHO bands. This calculator reports the raw index rather than a category for that reason — use it to track your own trend over time rather than as a diagnostic cutoff.

How is this different from waist-to-hip ratio?

Waist-to-hip ratio only compares two circumferences and ignores overall body size entirely, so two people with identical proportions but very different builds get the same ratio. The conicity index instead normalizes waist circumference against your weight and height together, which is meant to better capture how much your waist stands out relative to your overall frame.

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