What is waist-to-height ratio?

Waist-to-height ratio (WHtR) is calculated as:

WHtR = waist circumference / height

Both measurements must use the same units. The widely cited healthy threshold is WHtR < 0.5, often summarised as “keep your waist circumference to less than half your height.” This rule has been validated in multiple large population studies as a quick screening criterion for cardiometabolic risk, applicable across different ethnicities and age groups.

WHtR vs. BMI comparison

BMI (Body Mass Index) measures overall body size but cannot distinguish fat mass from lean mass, and does not indicate where fat is stored. WHtR specifically captures central adiposity (abdominal/visceral fat), which is more strongly associated with cardiovascular disease risk than peripheral fat.

A 2016 systematic review by Ashwell and Gibson found WHtR to be a better predictor of cardiometabolic risk factors than BMI across diverse populations. The 0.5 boundary identifies high-risk individuals across a wide range of heights and builds more consistently than BMI categories.

Measurement guide

Measure waist at the midpoint between the lowest rib and the top of the iliac crest - typically just above the navel.
Measure at the end of a normal exhale; do not suck in or push out.
The tape measure should be horizontal all the way around.
Do not measure over bulky clothing.
The most common error is placing the tape at the narrowest visible waist point rather than the anatomical midpoint.