How the waist-to-height calculator works
Why distribution outranks total
Visceral fat (around organs) is metabolically active in the harmful direction — insulin resistance, inflammation, lipid dysregulation — while subcutaneous fat is comparatively benign. Two identical-BMI people can differ completely in visceral load. Waist circumference is the cheapest proxy for that difference, and normalized to height it becomes one rule for every body: under 0.5.
The one-line guideline
"Keep your waist less than half your height" compresses the research into something you can remember at a buffet. It works across heights, sexes, and ethnicities better than fixed cutoffs (the 40-inch male / 35-inch female rules misfit at the extremes), and validation studies repeatedly find it predicts cardiometabolic risk at least as well as BMI — often better.
Measuring the waist correctly
At the navel (or the narrowest point if that differs), tape horizontal, relaxed exhale, no compressing the skin, mirror-check the level. Measure morning, before food. The pants-waist measurement — where jeans sit — is not the anatomical waist and underestimates by inches on most adults.