Free tool
Waist-to-height ratio calculator
Keep your waist to less than half your height. It is one of the simplest health guidelines there is, it needs one tape measure, and it predicts metabolic risk better than BMI does.
How to measure your waist properly
The measurement is more sensitive to technique than the arithmetic is to precision, so it is worth doing consistently.
Measure at the midpoint between the bottom of your ribs and the top of your hip bones — for most people that is roughly at or just above the navel, not at the waistband of your trousers. Stand upright, breathe out normally, and keep the tape snug without compressing the skin. Measure directly against skin or over a thin layer.
Do it at the same time of day each time, ideally in the morning before eating. Day-to-day variation of a centimetre or two is normal and means nothing.
What the bands mean
| Ratio | Category |
|---|---|
| Below 0.40 | Below the healthy range |
| 0.40 – 0.49 | Healthy |
| 0.50 – 0.59 | Increased health risk |
| 0.60 and above | Further increased health risk |
The headline rule — keep your waist under half your height — is the 0.5 boundary, and it is deliberately easy to remember. Someone 170 cm tall wants a waist under 85 cm; someone 180 cm tall, under 90 cm.
These boundaries apply to adults of all ethnicities, which is part of the appeal. Waist thresholds expressed in absolute centimetres need different cut-offs for South Asian and East Asian populations, because metabolic risk rises at a lower waist circumference. A ratio scales with body size on its own and sidesteps the problem.
Why it beats BMI
BMI is weight divided by height squared. It knows nothing about where the weight is, which is the single most important thing about it.
Fat stored around the abdomen — visceral fat, packed around the organs — is what drives insulin resistance, type 2 diabetes and cardiovascular risk. Fat on the hips and thighs is, metabolically, far less of a problem. BMI treats them identically.
This produces two well-known failures. Muscular people are classified as overweight when they are not, because muscle weighs more than fat. And people with a normal BMI but a large waist — the pattern sometimes called "normal weight obesity", which is notably common across South Asia — are told everything is fine when their metabolic risk is genuinely elevated.
Waist-to-height ratio catches both cases with one tape measure. It is not a complete picture either, but it is a better single number. BMI calculator → · Body fat calculator →
Frequently asked questions
What is a healthy waist-to-height ratio?
Between 0.40 and 0.49 for adults. The simplest way to remember it is that your waist should measure less than half your height.
Is waist-to-height ratio better than BMI?
For predicting metabolic and cardiovascular risk, generally yes. It accounts for where fat is stored, which BMI cannot, and it does not need different thresholds for different ethnicities. Neither number is a diagnosis on its own.
Does it differ for men and women?
No, and that is one of its advantages. The same 0.5 boundary applies to both, unlike absolute waist thresholds which need separate cut-offs by sex and by ethnicity.
Does it work for children?
The 0.5 guideline is often applied from about age six, but children's measurements should be interpreted by a paediatrician against growth charts rather than from a calculator.
How do I reduce my waist measurement?
Overall fat loss, which means a sustained calorie deficit. There is no way to target abdominal fat specifically — visceral fat does tend to respond early to a deficit, which is why waist often shrinks before the scale moves much. See what a calorie deficit is.
Is anything stored?
No. The calculation runs entirely in your browser. No sign-up, and no measurements are sent anywhere.
Next step
The measurement follows the deficit.
Waist responds to sustained fat loss, and fat loss follows from knowing what you eat. Describe the meal; BetterCal does the rest. Free to start on iPhone and Android.
