The waist-to-height ratio (WHtR) is the simplest and arguably most informative single number for visceral abdominal fat — and therefore for the risk of cardiovascular disease, type 2 diabetes and the metabolic syndrome.
This article covers the formula, the Ashwell classification, how to measure correctly, and why WHtR outperforms BMI as a risk marker.
The Formula
WHtR = waist circumference ÷ height
both in the same unit (cm)
Rule of thumb: keep your waist below half your height. At 175 cm, that means a waist below 87.5 cm. Margaret Ashwell and colleagues established this «half-waist rule» in a 2012 meta-analysis as a robust screening criterion across populations.
Ashwell Classification (2012)
| Category | WHtR (under 40) | WHtR (over 50) |
|---|---|---|
| Underweight | < 0.40 | < 0.40 |
| Low risk | 0.40 – 0.49 | 0.40 – 0.54 |
| Increased | 0.50 – 0.54 | 0.55 – 0.59 |
| Substantially increased | 0.55 – 0.59 | 0.60 – 0.64 |
| Very high risk | ≥ 0.60 | ≥ 0.65 |
Between ages 40 and 50 the boundaries shift up by 0.005.
Worked Example
A 35-year-old woman with a waist of 85 cm and height of 175 cm:
85 cm ÷ 175 cm = 0.486
Result: low risk per Ashwell.
Calculate your WHtR now
Ashwell-based risk classification — free, instant, no sign-up.
Open WHtR calculator →How to measure correctly
Measure in the morning, fasted, standing upright. Place the tape horizontally at navel height, snug but without compressing the skin. Exhale normally and hold the breath for the measurement. For accuracy, repeat twice and take the mean.
Measure height barefoot against a wall, with a straight back and head facing forward.
WHtR vs. BMI vs. WHR
BMI uses only weight and height — it can't tell muscle from fat and ignores fat distribution. The waist-to-hip ratio (WHR) captures distribution but requires two circumferences.
WHtR combines the strengths: it captures abdominal fat with one extra measurement and scales across heights and sexes. In meta-analyses it predicted cardiometabolic risk better than both BMI and WHR.
Bottom line
WHtR is fast to compute, easy to measure, and one of the most reliable single-number markers of visceral fat. Use our WHtR calculator and combine it with BMI and body fat for a complete picture.
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