Riepilogo
Waist-to-hip ratio (WHR) is a simple measure of abdominal fat distribution. You divide your waist circumference by your hip circumference. The WHO uses it as an indicator of cardiovascular and metabolic risk — the INTERHEART study (52 countries, 27,000 participants) found WHR was a stronger predictor of heart attack risk than BMI.
Come funziona
WHR measures where your body stores fat. Fat around the abdomen (apple shape) is more strongly linked to cardiovascular disease and type 2 diabetes than fat around the hips and thighs (pear shape). A higher WHR means more central fat accumulation relative to hip size.
The calculator also provides a standalone waist circumference risk assessment using WHO/NICE thresholds, which captures absolute abdominal fat independently of hip size.
La formula
Where
WHO WHR risk thresholds
The WHO (2008) defines a single cutoff for abdominal obesity. Our calculator extends this into three categories for clinical clarity:
| Risk level | Men | Women |
|---|---|---|
| Low | WHR < 0.90 | WHR < 0.80 |
| Moderate | WHR 0.90 – 0.99 | WHR 0.80 – 0.84 |
| High | WHR ≥ 1.00 | WHR ≥ 0.85 |
The WHO’s official threshold for “substantially increased risk” is ≥ 0.90 for men and ≥ 0.85 for women. The Moderate/High subdivision above the WHO cutoff is a common clinical interpretation.
Waist circumference risk thresholds (WHO/NICE)
Independent of hip size, waist circumference alone predicts metabolic risk:
| Risk level | Men | Women |
|---|---|---|
| Low | < 94 cm | < 80 cm |
| Increased | 94 – 101 cm | 80 – 87 cm |
| Substantially increased | ≥ 102 cm | ≥ 88 cm |
Source: Lean et al. (1995), adopted by WHO (2008) and NICE CG189 (2014).
Esempio pratico
Male: waist 92 cm, hip 100 cm
Divide waist by hip
= 0.92
Classify WHR (male thresholds)
= Moderate risk
Classify waist circumference (male)
= Low waist risk
Result
WHR = 0.92 (Moderate cardiovascular risk), waist circumference = Low risk. This person has a borderline WHR but their waist alone is still below the increased-risk threshold.
How to measure
- Waist: Use a flexible, non-stretch tape measure. Measure at the narrowest point of the torso — typically midway between the bottom of the ribs and the top of the hip bone (iliac crest), roughly at navel level. Measure at the end of a normal exhale.
- Hip: Measure at the widest point of the buttocks. Keep the tape horizontal and parallel to the floor.
- General: Stand upright, feet together, arms relaxed at your sides. The tape should be snug but not compressing the skin.
Input spiegati
- Sex — thresholds differ between men and women because fat distribution patterns differ by sex.
- Waist circumference — measured in cm (metric) or inches (imperial).
- Hip circumference — measured in cm or inches. The calculator converts imperial to metric internally.
- Unit toggle — switch between metric (cm) and imperial (inches). Values auto-convert when toggling.
Output spiegati
- WHR value — the ratio itself (dimensionless, typically between 0.60 and 1.20).
- WHR risk category — Low, Moderate, or High based on WHO thresholds for the selected sex.
- WHR scale — visual representation showing where your ratio falls on the risk spectrum.
- Waist circumference risk — separate assessment using WHO/NICE standalone waist thresholds.
- Measurements summary — your entered waist and hip values for reference.
Ipotesi e limitazioni
- Ethnicity-specific thresholds not included. The WHO acknowledges that optimal cutoffs may vary by ethnicity (e.g., lower thresholds for South Asian and East Asian populations). This calculator uses the standard WHO/European thresholds.
- Not suitable for children or adolescents. These thresholds were derived from adult populations.
- Not suitable during pregnancy.
- Measurement technique matters. Small differences in tape placement (above vs. at the navel) can shift WHR by 0.02–0.05. Follow the WHO protocol for consistent results.
- Snapshot, not a diagnosis. WHR is one component of metabolic risk assessment. Clinical evaluation considers blood pressure, blood glucose, lipid profile, and family history alongside anthropometric measures.
Verifica
| Test case | Waist (cm) | Hip (cm) | Sex | Expected WHR | WHR risk | Waist risk |
|---|---|---|---|---|---|---|
| Average male | 85 | 100 | M | 0.850 | Low | Low |
| Average female | 70 | 95 | F | 0.737 | Low | Low |
| Male at WHO cutoff | 90 | 100 | M | 0.900 | Moderate | Low |
| Female at WHO cutoff | 85 | 100 | F | 0.850 | High | Increased |
| High-risk male | 105 | 100 | M | 1.050 | High | Sub. increased |
All values verified by hand calculation (WHR = waist ÷ hip) and cross-checked against WHO thresholds.
Sources
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