VitalMetrics

Waist-to-Height Ratio Calculator

Divide your waist by your height. If the answer is under 0.5, your waist is less than half your height, the simple target UK health guidance recommends.

Units
ft
in
lb
in
Midway between lowest rib and top of hip bone, after breathing out
0.48waist ÷ heightHealthy
Take care
Healthy
Increased risk
High risk
Waist-to-height ratio: 0.48, Healthy
Half your height
32.5 in
Your waist
31.5 in
Room below 0.5
1.0 in
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Explain my result

Sends only the numbers shown above (no name, no account) to an AI model through Vercel AI Gateway. It explains; it doesn’t diagnose.

The half-your-height rule, visualised

Take a piece of string as long as you are tall, fold it in half, and wrap it round your waist. If the ends meet, your waist is under half your height. This works at any height, which is why NICE adopted it in 2022. Drag the sliders.

88 ÷ 170 = 0.52 · Increased risk

NICE waist-to-height bands

RatioCentral adiposityWhat it indicates
0.40–0.49HealthyNo increased health risk
0.50–0.59IncreasedIncreased health risk
0.60 or moreHighFurther increased health risk

Why the middle matters

Fat stored deep in the abdomen, around the liver and other organs, is more metabolically active than fat under the skin on hips and thighs. It’s tied to insulin resistance, raised blood pressure and unhealthy cholesterol. Two people with the same BMI can have very different waist sizes, which is why a large 2012 meta-analysis by Ashwell and colleagues found waist-to-height ratio predicted cardiometabolic risk better than BMI.

If your ratio is 0.5 or above, it’s a reason for a conversation with your GP or doctor, who may check blood pressure, blood sugar and cholesterol. It isn’t a diagnosis.

Questions people ask

What is a healthy waist-to-height ratio?

UK NICE guidance (2022) uses 0.4 to 0.49 as healthy, 0.5 to 0.59 as increased health risk and 0.6 or more as high risk. In plain terms: keep your waist to less than half your height.

Is waist-to-height ratio better than BMI?

It adds something BMI misses: where fat is stored. Fat around the organs is most linked to type 2 diabetes and heart disease, and waist size reflects it. NICE recommends using it alongside BMI for adults with a BMI under 35.

How do I measure my waist correctly?

NICE advises finding the top of your hip bone and the bottom of your ribs, breathing out naturally, and wrapping the tape midway between them. Don’t pull it tight or measure over clothing.

Does the 0.5 rule apply to everyone?

NICE applies the same bands to adults of all ethnicities and sexes. It is not designed for children, pregnant women, or people with a BMI of 35 or more, and very muscular people may need a clinician’s interpretation.

Sources

  1. NICE (2022). Obesity: identification, assessment and management (CG189), updated recommendations on waist-to-height ratio.
  2. Ashwell M, Gunn P, Gibson S (2012). Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obes Rev 13:275–286.
  3. World Health Organization (2008). Waist circumference and waist–hip ratio: report of a WHO expert consultation (measurement protocol).

Every formula on VitalMetrics is listed with its original reference on Sources & methods.

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