Waist-to-hip ratio (WHR) is one of the simplest and most clinically validated measures of how body fat is distributed. While BMI tells you whether your weight is proportionate to your height, WHR reveals where that fat sits — and where fat sits turns out to matter enormously for cardiovascular and metabolic health. The World Health Organisation recommends WHR as a standard screening tool alongside BMI in population health surveys and clinical practice.
This calculator goes beyond a plain WHR readout. It shows your WHO risk band, classifies your body shape (pear, hourglass or apple), tells you your target waist circumference to reach the low-risk band, and includes a solve-for-waist mode that inverts the formula so you can set a ratio goal and see exactly what waist size to aim for. Everything runs in your browser — no measurements leave your device.
How it works
The formula is disarmingly simple:
WHR = waist circumference ÷ hip circumference
Because you divide one length by another in the same unit, the unit cancels — a ratio of 0.85 is 0.85 whether you measure in centimetres or inches. The calculator accepts both; switching units automatically converts your existing inputs.
Once WHR is computed, it is compared against the WHO 2008 sex-specific thresholds:
| Sex | Low risk | Moderate risk | High risk |
|---|---|---|---|
| Male | WHR below 0.90 | 0.90–0.99 | 1.00 and above |
| Female | WHR below 0.80 | 0.80–0.84 | 0.85 and above |
Women naturally store more fat on the hips and thighs (a lower WHR), which is why the female thresholds are lower. Applying the male thresholds to a female would incorrectly under-classify risk, so the calculator always uses the band matching the sex you select.
Body shape classification
WHR also maps to the familiar apple / pear distinction, which researchers use as a shorthand for central versus peripheral fat distribution:
- Pear — WHR is low; fat concentrates on the hips and thighs. Associated with lower cardiovascular risk.
- Hourglass (women) / Rectangular (men) — intermediate, balanced distribution.
- Apple — WHR is high; fat concentrates around the abdomen. Associated with higher metabolic and cardiovascular risk.
The classification thresholds used here are: for women, pear below 0.75, hourglass 0.75–0.80, apple above 0.80; for men, pear below 0.85, rectangular 0.85–0.95, apple above 0.95.
Solve-for-waist mode
Sometimes the useful question is not “what is my WHR?” but “what waist do I need to reach a healthy ratio?” Rearranging the formula:
waist = hip × target WHR
Enter your hip circumference and the WHR you want to achieve and the calculator shows the exact waist size to aim for, with its corresponding risk band. This is useful for setting a concrete fitness goal rather than tracking an abstract ratio.
Worked example
A woman with a 90 cm waist and 108 cm hips:
- WHR = 90 ÷ 108 = 0.833
- Risk band: moderate (female moderate: 0.80–0.84)
- Body shape: apple
- Target waist for low risk: 108 × 0.795 ≈ 85.9 cm (using the top of the low-risk range)
- Reduction needed: 90 − 85.9 = ≈ 4.1 cm
The same calculation for a man would yield a different risk classification because the male low-risk threshold is 0.90, not 0.80.
Measurement tips
Accuracy matters because a small error in measurement produces a real change in the ratio:
- Waist: stand upright, breathe out naturally, measure the narrowest horizontal circumference — usually 2–3 cm above the navel.
- Hips: keep feet together, measure the widest horizontal circumference around the buttocks.
- Hold the tape parallel to the floor, snug but not compressing the skin.
- Measure without heavy clothing and record to the nearest 0.5 cm or 0.5 inch.
- Repeat twice and average if readings differ by more than 1 cm.
WHR is a screening indicator, not a clinical diagnosis. Changes in waist size due to posture, digestion, or time of day can shift the ratio by a few hundredths. For decisions about your health, use WHR alongside other measures and consult a healthcare professional.