Body composition calculator
Conicity index calculator
How much wider than a cylinder are you at the middle? Enter waist, weight and height — no hip measurement needed. Free, instant, no sign-up.
One index is a snapshot. The coach builds the plan that moves it.
What is the conicity index?
The conicity index, proposed by Valdez in 1991, asks one geometric question: how much wider than a cylinder are you at the waist? It compares your actual waist with the waist that a cylinder of your exact mass and height would have. A perfect cylinder scores 1.00. A perfect double cone — two cones joined at the middle — scores the square root of three, about 1.73. Real bodies land between, and the higher the number, the more of your mass is concentrated at the middle.
How this calculator works
The index is waist in metres divided by 0.109 times the square root of weight in kilograms over height in metres. The constant is not arbitrary: work out the circumference of a cylinder with your mass, your height and the density of the human body, roughly 1,050 kg per cubic metre, and 0.109 is what the algebra collapses to. This page shows you that cylinder waist in centimetres alongside the index, because the ratio is easier to trust once you can see the number it is dividing by.
Why not just use waist-to-hip?
Because the conicity index has no hip term. Waist-to-hip breaks whenever the hips change for reasons unrelated to metabolic risk — dieting takes fat off the hips and raises the ratio, adding glute mass lowers it — and the denominator moves independently of the thing you are trying to measure. Conicity replaces the hip measurement with mass and height, which you already know. It also has an advantage over raw waist circumference: it is already normalised for how much body the waist belongs to, so a 95 cm waist on a 195 cm frame is not read the same as a 95 cm waist on a 160 cm one.
Where the evidence is thin
The cutoffs. Valdez published the index without a clinical threshold, and there is no WHO or consensus figure for it in the way there is for waist circumference. The numbers this page shows — 1.25 for men and 1.18 for women — come from Pitanga and Lessa's 2004 analysis of 968 Brazilian adults, and are labelled as such rather than presented as universal. Treat the index as a way of tracking your own shape over time rather than as a line you pass or fail. If you want a single number with wide support behind it, use waist-to-height.