CalcVitalsWaist-to-Height Ratio Calculator
Waist-to-height ratio is your waist measurement divided by your height, and the public-health message is one line: keep your waist to less than half your height — a ratio under 0.5. A waist of 85 cm at 175 cm tall gives 0.49, just inside the line.
How it works
Of all the simple body measurements, waist-to-height ratio has the best claim to being the one number worth knowing. Fat carried around the abdomen — visceral fat, packed around the organs — is the fat that drives type 2 diabetes, heart disease and fatty liver, and this ratio captures it directly, where BMI cannot see distribution at all.
Large reviews comparing screening measures have repeatedly found waist-to-height ratio at least as good as BMI at flagging cardiometabolic risk, and often better, with one cut-off — 0.5 — serving men, women and most ethnic groups. That is a rare thing in health screening: a rule a child can apply with a piece of string. Measure your height with the string, fold it in half, and it should go around your waist.
Measure the waist at the navel, relaxed, at the end of a normal breath. Tracked monthly, the trend in this ratio tells you more about whether a lifestyle change is working than the bathroom scale does — weight can stall while the waist, and the risk, quietly shrink.
The method
WHtR = waist circumference ÷ height, same units. Boundary values from Ashwell's research and NICE-aligned guidance: below 0.4 low, 0.4–0.49 healthy, 0.5–0.59 increased risk, 0.6 and above high risk. Waist measured at the navel (WHO midpoint method gives near-identical ratios for most bodies).
Frequently asked questions
Is waist-to-height better than BMI?
For predicting diabetes and cardiovascular risk, studies generally find it equal or better, because it captures abdominal fat, which BMI ignores entirely. Many clinicians now suggest using both: BMI for overall mass, this ratio for distribution.
Where do I measure my waist for this?
At the level of your navel, standing relaxed, tape horizontal and snug without compressing the skin, at the end of a normal exhale. Consistency matters more than the exact landmark.
Does the 0.5 rule apply to children?
Broadly yes — the same boundary is used in paediatric screening, though children's results should always be read with a clinician, since growth changes proportions quickly.