Waist-to-Height Ratio Calculator

What is WHtR?

The waist-to-height ratio ($\text{WHtR}$, or WSR: waist-to-stature ratio) is a simple metric calculated by dividing your waist circumference by your body height. Both measurements must be in the same units (e.g., centimeters or inches) for an accurate ratio.

$\text{WHtR} = \frac{\text{Waist Circumference}}{\text{Height}}$

WHtR is a key measure of the distribution of body fat . Higher values indicate a greater risk of obesity-related cardiovascular diseases, which are strongly correlated with abdominal obesity . A waist size that is less than half your height is generally considered a healthy indicator.

History and Significance

WHtR was first proposed as a health risk assessment tool over twenty-five years ago, serving as a proxy for harmful central adiposity . It effectively predicts obesity-related cardiovascular disease. A boundary value of 0.5 was suggested early on to indicate increased risk.

A 2010 systematic review concluded that WHtR offers advantages because "it avoids the need for age-, sex- and ethnic-specific boundary values," making it a universal and straightforward indicator.

Measurement Guideline: According to World Health Organization (WHO) guidance, the waist circumference is usually measured midway between the lower rib and the iliac crest (the top of your hip bone).

Recommended Boundary Values (NICE Guidelines)

The UK's National Institute for Health and Care Excellence (NICE) formally adopted guidelines in September 2022, advising adults to "ensure their waist size is less than half their height in order to help stave off serious health problems."

NICE recommends the following boundary values for WHtR, which define the degree of "central adiposity" (abdominal obesity) and corresponding health risks:

These classifications are applicable for people with a Body Mass Index (BMI) of under 35, for both sexes and all ethnicities, including adults with high muscle mass. The health risks associated with higher levels of central adiposity include type 2 diabetes, hypertension, and cardiovascular disease. NICE also suggests the same boundary values for children aged 5 years and over.

Age-Adjusted Boundary Values

A 2013 study identified critical threshold values for WHtR according to age, with significant reduction in life expectancy if exceeded:

• WHtR greater than 0.5 for people under 40 years of age.
• WHtR 0.5 to 0.6 for people aged 40–50 .
• WHtR greater than 0.6 for people over 50 years of age.

WHtR as a Public Health Tool

WHtR is a highly effective proxy for central (visceral or abdominal) adiposity . Its values are significantly correlated with direct measures obtained from advanced techniques like CT, MRI, or DEXA scans.

Several systematic reviews and meta-analyses consistently show the superiority of WHtR over BMI and simple waist circumference in predicting early health risk in adults of all ages, as well as in children and adolescents. It's often preferred for its simplicity and because it generally doesn't require sex- and age-dependent cut-offs.

Crucially, WHtR not only has a close relationship with morbidity (illness) but also a clearer relationship with mortality than BMI. Even within the "normal" BMI range, many individuals have a WHtR above 0.5, indicating increased risk for metabolic diseases and mortality.

The simplified guideline remains: "Keep your waist to less than half your height."