How do you calculate your waist-to-hip ratio?

Divide your waist circumference by your hip circumference, both measured in the same unit. For example, a waist of 88 cm and hips of 102 cm give 88 ÷ 102 = 0.86.

What waist-to-hip ratio is considered normal?

The WHO sets the substantially-increased-risk cut-off at 0.90 for men and 0.85 for women. Below it, this indicator flags nothing in particular; above it, it is worth raising with a health professional.

Where exactly do you put the tape measure?

The waist is measured midway between the lowest rib and the top of the iliac crest, at the end of a normal breath out; the hips at the widest point over the buttocks. Keep the tape horizontal and touching the skin without compressing it — a couple of centimetres off is enough to change the category.

Waist-to-hip ratio or BMI: which one should you look at?

They answer different questions. BMI describes total mass relative to height; the waist-to-hip ratio describes where the fat sits. In the INTERHEART study, the ratio was more strongly associated with heart attack risk than BMI. In practice, track both, along with waist circumference.

Waist-to-hip ratio calculator

Enter your waist and hip measurements: the calculator returns your waist-to-hip ratio, places it against the WHO cut-off for your sex and explains what the result points to — and what it does not.

About 30 seconds

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The formula used

Waist-to-hip ratio = waist circumference (cm) ÷ hip circumference (cm)
The result is a dimensionless ratio: measuring in inches gives exactly the same number, as long as both circumferences use the same unit.

For a waist of 88 cm and hips of 102 cm, the waist-to-hip ratio is 0.86. The WHO risk cut-off is 0.90 for men and 0.85 for women.

Thresholds from the World Health Organization: “Waist circumference and waist–hip ratio: report of a WHO expert consultation”, Geneva, 8–11 December 2008 (published 2011), Table A1 — a ratio of 0.90 in men and 0.85 in women corresponds to a substantially increased risk of metabolic complications.

Reference thresholds by sex

Risk level	Men	Women
Low	Below 0.90	Below 0.85
Moderate	0.90 to 0.99	0.85 to 0.89
High	1.00 and above	0.90 and above

The WHO publishes a single cut-off per sex: the one separating “low” from “moderate” here. Above it, risk keeps rising gradually — in the INTERHEART study (Lancet, 2005), the fifth of participants with the highest ratios were around 2.5 times more likely to have had a heart attack than the fifth with the lowest. The second line (1.00 for men, 0.90 for women) is a marker in common practice, not a WHO threshold.

How to take the measurements

Waist: standing, feet together, measure midway between the lowest rib and the top of the iliac crest, at the end of a normal breath out, without pulling your stomach in.
Hips: measure at the widest point over the buttocks, keeping the tape horizontal and against the skin without compressing it.
Take each measurement twice and keep the average if the two differ by more than 1 cm. Repeat under the same conditions — same time of day, same light clothing — so comparisons over time actually mean something.

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