Health & Wellbeing
Waist-to-Height Ratio
A simple check of fat carried around the middle.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
Waist-to-height ratio divides your waist circumference by your height in the same units. It estimates central adiposity — fat carried around the middle — which is more closely linked to type 2 diabetes, hypertension and cardiovascular disease than overall weight is. NICE recommends it in adults with a BMI below 35 kg/m2, used alongside BMI rather than instead of it, and gives the memorable version: keep your waist to less than half your height.
Interpreting the result
NICE classifies the result in three bands: 0.4 to 0.49 is healthy central adiposity with no increased health risks; 0.5 to 0.59 is increased central adiposity indicating increased health risks; and 0.6 or more is high central adiposity indicating further increased health risks. NICE states these classifications can be used in people with a BMI under 35 kg/m2 of both sexes and all ethnicities, including adults with high muscle mass. Above a BMI of 35 the ratio adds little, because central adiposity can be assumed, and NICE does not apply the bands there.
Advice
Measure your waist midway between the bottom of your ribs and the top of your hips, after breathing out. Keeping your waist under half your height helps lower the risk of heart disease and type 2 diabetes.
Worked example
NICE's own worked example: a waist of 96.5 cm and a height of 170 cm gives 96.5 / 170 = 0.57 — increased central adiposity, indicating increased health risks and worth acting on. The same person in inches, 38 divided by 67, gives the same 0.57.
Pearls / pitfalls
- Measurement technique changes the answer: measure midway between the bottom of your ribs and the top of your hips, directly against the skin, after breathing out normally — not sucked in, and not over bulky clothing.
- The bands apply to adults with BMI under 35 kg/m2. Above that, NICE does not use waist-to-height ratio for classification.
- It works across both sexes and all ethnicities, which is a practical advantage over waist circumference alone, where cut-offs differ by ethnic group.
- A ratio in the healthy band does not rule out cardiometabolic risk — blood pressure, lipids, glucose, family history and smoking all matter independently.
Evidence & validation
The thresholds come from NICE guideline NG246 (Overweight and obesity management), recommendations 1.9.8, 1.9.14 and 1.9.15. NG246 was published on 14 January 2025 and last updated on 8 January 2026, and replaces CG43, CG189, NG7, PH42, PH47 and PH53. The advice to measure waist-to-height ratio alongside BMI in adults with BMI below 35 kg/m2 was introduced in the 2022 update to the guidance it supersedes.
Frequently asked questions
What is a healthy waist-to-height ratio?
NICE classifies 0.4 to 0.49 as healthy central adiposity with no increased health risks. The simple version is to keep your waist to less than half your height.
Where exactly do I measure my waist?
Midway between the bottom of your ribs and the top of your hip bones, against the skin, breathing out normally. Do not measure at the navel by default and do not pull the tape tight.
Is it better than BMI?
It is complementary. NICE recommends using it alongside BMI in adults with BMI below 35, because it captures where fat is carried, which BMI cannot.
Does it apply if I am very muscular?
Yes — NICE states the classifications can be used in adults with high muscle mass, which is one reason it is useful where BMI can mislead.
Does it work for children?
Waist-to-height ratio is used in children and young people aged 5 years and over, but the interpretation differs from adults. Use NHS resources aimed at that age group rather than these adult bands.
References
- NICE NG246: Overweight and obesity management. Published 14 January 2025, last updated 8 January 2026. Recommendations 1.9.8, 1.9.14 and 1.9.15.
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