Waist-to-height ratio calculator

It says where the fat sits, not just how much you weigh. Body mass index does not distinguish the fat around the organs from the rest of the weight, and the metabolic risk comes mostly from the former. An analysis of more than 300000 adults showed that the waist-to-height ratio distinguishes better, compared with body mass index, patients with hypertension, type 2 diabetes and dyslipidemia [1].

The two do not exclude each other. The most useful thing is to calculate them together, and you can get your body mass index with the BMI calculator. The ratio is not interpreted the same way in children, athletes, pregnant women or older adults. In pregnancy the waist grows for a different reason, so the figure says nothing about risk. The cut-offs that separate the four bands are 0.4, 0.5 and 0.6:

• below 0.4 — below the reference range;
• from 0.4 to 0.5 — in the reference range;
• from 0.5 to 0.6 — increased risk;
• 0.6 and above — substantially increased risk.

Halfway between the lower edge of the ribs and the crest of the hip bone, on bare skin. Measure at the end of a normal breath out, without pulling the tape tight and without holding your stomach in.

Timing matters. In the morning, before eating, the figure is more stable. A difference of two or three centimetres between two measurements of the same person is ordinary, so do not read the ratio to a precision the measurement does not have.

Because it translates into a rule that is easy to remember, namely that the waist is better kept under half your height. The boundary does not depend on sex, nor on population, unlike the circumference thresholds, which differ between Europeans and Asians.

A study of adults in the United Kingdom showed that 35% of the people judged to be at no increased risk by body mass index and waist circumference nonetheless had a ratio above 0.5, and that this group already had higher values of blood pressure, triglycerides and glycated hemoglobin [2].

In European populations 94 cm and 102 cm are used for men, and 80 cm and 88 cm for women. The first figure marks an increased circumference, the second a substantially increased one. The calculator shows them only after you pick a sex.

In South and East Asian populations the thresholds are lower, because the metabolic risk appears at smaller circumferences. This is exactly the limitation the waist-to-height ratio overcomes, which is one of the reasons this ratio is the headline result of this page.