Waist-to-hip ratio calculator

Where fat is carried predicts health risk better than how much of it there is. This is the cheapest way to measure that.

Why shape matters more than weight

Two people can share a BMI and face very different risks. Fat stored around the abdomen — visceral fat, packed between the organs — is metabolically active and associated with insulin resistance, type 2 diabetes and cardiovascular disease. Fat stored on the hips and thighs is far less strongly associated with any of them.

Waist-to-hip ratio is a crude but effective way to detect which pattern you have, and it needs nothing but a tape measure. In the INTERHEART study, which looked at heart attack risk across 52 countries, waist-to-hip ratio was a substantially better predictor than BMI.

The thresholds

World Health Organization guidance puts substantially increased risk at:

Men — 0.90 and above is moderate, 1.00 and above is high
Women — 0.80 and above is moderate, 0.85 and above is high

The difference between the sexes reflects typical fat distribution rather than any difference in how dangerous abdominal fat is. These are population thresholds and they shift somewhat between ethnic groups — several studies suggest lower cut-offs are appropriate for South Asian and East Asian populations.

Waist-to-height is simpler and may be better

If you entered a height, the calculator also shows waist divided by height. The rule is memorable: keep your waist under half your height. A ratio below 0.5 is the healthy range.

It needs one fewer measurement than WHR, removes the hip measurement (the one people get wrong most often), and performs at least as well in most studies. It also works across a wider range of ages and body types without separate thresholds by sex.

Measuring it properly

Consistency matters more than precision, since you will mostly use this to track change:

Measure directly against skin, or over a single thin layer.
Waist at the narrowest point between the lowest rib and the hip bone — usually just above the navel. If there is no obvious narrowest point, use the level of the navel.
Hips at the widest point around the buttocks.
Stand relaxed, feet together, arms at your sides. Breathe out normally and measure at the end of that breath. Do not hold your stomach in.
The tape should be snug enough not to slip, but not compressing the skin. Keep it horizontal all the way round — a mirror helps.

Measure at the same time of day, ideally in the morning before eating, since abdominal girth changes by a centimetre or more across a day.

Common questions

What is a healthy waist-to-hip ratio?

Under 0.90 for men and under 0.80 for women is the low-risk band in WHO guidance. Above 1.00 for men and 0.85 for women is considered high risk.

Is waist-to-hip ratio better than BMI?

For predicting cardiovascular and metabolic risk, generally yes. BMI cannot tell where fat is stored or distinguish muscle from fat, while WHR directly reflects abdominal fat distribution. The two measure different things and are best read together.

Where exactly should I measure my waist?

At the narrowest point between your lowest rib and the top of your hip bone, usually just above the navel. If you have no obvious narrowest point, use the navel level and stay consistent between measurements.

Is waist-to-height ratio easier to use?

Yes, and it performs at least as well. Keep your waist under half your height — a ratio below 0.5. It needs one fewer measurement and does not require separate thresholds by sex.