Waist-to-height ratio
- NICE advises keeping your waist to less than half your height — a ratio below 0.5.
- A ratio of 0.5 to 0.59 means increased health risk; 0.6 or more means high risk.
- The same boundaries apply to adults of every ethnic background, and the ratio is useful even when your BMI is in the healthy range.
Why fat around the middle matters
Fat stored deep inside the abdomen, around the liver and other organs, behaves differently from fat under the skin. It is closely linked with insulin resistance, type 2 diabetes, high blood pressure, raised cholesterol, fatty liver and heart disease. Because BMI only looks at total weight, two people with the same BMI can have very different levels of risk. Your waist-to-height ratio helps tell them apart.
What your ratio means
| Ratio | What it suggests |
|---|---|
| Below 0.4 | May indicate being underweight — worth discussing with your GP |
| 0.4 – 0.49 | Healthy — no increased risk from central fat |
| 0.5 – 0.59 | Increased health risk |
| 0.6 and above | High health risk |
Measuring correctly
Measure halfway between your lowest rib and the top of your hip bone, after breathing out normally. Our step-by-step guide to measuring your waist explains the common mistakes that make the number less accurate.
Bringing your ratio down
Central fat often responds well to the same changes that improve overall health: a modest calorie deficit, enough protein, regular movement — including strength training — limiting alcohol, and sleeping well. Many people see their waist shrink before their weight changes much.
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Our free online assessment takes about five minutes. A GPhC-registered prescriber reviews it and only recommends treatment if it is safe and suitable for you.
Start the free assessmentFrequently asked questions
Is waist-to-height ratio better than BMI?
They answer different questions. BMI looks at overall weight; waist-to-height ratio shows central fat, which is closely linked to heart and metabolic risk. NICE recommends using both for adults with a BMI under 35.
Can I use inches instead of centimetres?
Yes. The ratio works in any unit, as long as your waist and height are measured in the same unit. The calculator converts for you.
How often should I measure my waist?
Once a month is plenty. Measure at the same time of day, in the same place, so the numbers are comparable.
This page is general health information. It does not replace advice from your GP or another healthcare professional who knows your history. If you have symptoms that worry you, contact your GP or NHS 111; in an emergency call 999. Prescription treatment is only supplied after an assessment by a registered prescriber.