Waist-to-Height Ratio Calculator
Calculate your waist-to-height ratio — a simple central-obesity screen.
Results update as you type.
About this calculator
A waist-to-height ratio (WHtR) calculator divides your waist circumference by your height. The simple public-health rule is to "keep your waist to less than half your height", so a ratio under 0.5 is the healthy target for most adults. Research suggests WHtR predicts cardiometabolic risk at least as well as BMI while being easy to measure.
The calculation is waist ÷ height in the same units. An 85 cm waist and 175 cm height give 85 ÷ 175 = 0.49, just inside the healthy range, and the tool reports a healthy maximum waist of 87.5 cm (half of 175). Ratios of 0.5–0.6 indicate increased risk and above 0.6 high risk. The single 0.5 threshold applies across most ages and both sexes, which makes the screen easy to remember.
Use WHtR as a quick check of central (abdominal) fat, the kind most linked to heart and metabolic disease. It needs only one circumference plus your height and, unlike waist-to-hip ratio, does not require a hip measurement. Measure the waist midway between the lowest rib and the top of the hip bone. It is a screening guide, not a medical diagnosis.
Frequently asked questions
What is a healthy waist-to-height ratio?
Below 0.5 is the widely-used healthy cut-off — your waist should be less than half your height. Ratios of 0.5–0.6 suggest increased risk and above 0.6 high risk.
How does WHtR compare to BMI?
WHtR directly measures central fat, which is the more dangerous kind, and applies the same 0.5 threshold across ages and sexes. Several studies find it predicts heart and metabolic risk as well as, or better than, BMI.
What should my waist size be for my height?
Keep your waist under half your height. At 175 cm that means a waist below about 87.5 cm (roughly 34.5 in); the tool shows this healthy maximum for the height you enter.
Does waist-to-height ratio work for all ages?
The 0.5 threshold applies to most adults regardless of age or sex, which is part of its appeal. Children and adolescents use age-specific charts instead of the flat cut-off.
How do I measure my waist for WHtR?
Measure at the midpoint between the lowest rib and the top of the hip bone (roughly the navel), with the tape level and snug after a normal breath out. Use the same units for waist and height so the ratio is correct.
Is WHtR or waist-to-hip ratio better?
Both screen for central fat. WHtR needs only one circumference plus height and uses a single 0.5 cut-off, while WHR compares waist to hips; many researchers favour WHtR for its simplicity.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/waist-to-height-ratio/curl
curl "https://calculator.free/api/v1/waist-to-height-ratio/?units=metric&waist=85&height=175"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/waist-to-height-ratio/?" + new URLSearchParams({
"units": "metric",
"waist": "85",
"height": "175"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.