Is your waist under half your height?
One tape measure, two numbers.
Measuring in
Find the bottom of your ribs and the top of your hips, and put the tape halfway between them, which is usually just above the navel. Breathe out normally. Do not pull it tight and do not hold your stomach in.
What your waist-to-height ratio means
| Ratio | What it is called | What it indicates |
|---|---|---|
| Under 0.4 | Below the healthy band | Under 0.4 is below the band NICE calls healthy. Worth a word with a doctor if it is not deliberate. |
| 0.4 to 0.49 | Healthy central adiposity | No increased health risks in the NICE bands. |
| 0.5 to 0.59 | Increased central adiposity | Increased health risks. This is the band where waist matters more than weight. |
| 0.6 and over | High central adiposity | Further increased health risks. Worth raising at an appointment. |
The same thresholds for both sexes and all ethnicities, and for children from age five. Not to be used as the assessment at a BMI of 35 or over. Source: NICE guideline NG246, January 2026.
For the waist measurement
A soft cloth or fiberglass tape, about $5. A metal builder’s tape will not sit flat around a waist and a piece of string held against a ruler does the job free, so buy one only if you will measure often.
Buying through this link supports the free library with a small commission. It never changes a pick.
Divide your waist by your height, in the same units. Under 0.5 is the healthy band, 0.5 to 0.59 indicates increased health risk, and 0.6 or more indicates further increased risk. NICE adopted these thresholds in January 2026 for both sexes, every ethnicity, and explicitly for people with a lot of muscle, which is the group BMI reads wrong most often. The public instruction is one sentence: keep your waist to less than half your height.
Where does BMI fit, then?
BMI is still the starting point in most guidelines and it is still the number your records will carry. It is also blind to where fat sits and misreads muscular people entirely. Run both, and take the worse of the two seriously.
Common questions
What is a healthy waist to height ratio?
Under 0.5. The guideline wording is as simple as the arithmetic: keep your waist to less than half your height. Between 0.4 and 0.49 is the healthy band, 0.5 to 0.59 indicates increased health risks, and 0.6 or more indicates further increased risk. The same thresholds apply to both sexes and to every ethnicity.
Is waist to height ratio better than BMI?
For some purposes, and the honest answer is narrower than the claim you usually see. It catches central fat in people whose BMI reads normal, it needs no separate cutoffs by ethnicity, and it works on someone with a lot of muscle, which is exactly where BMI misleads. What it does not do is predict death better than BMI: the largest recent test, 94,401 people and 48,323 deaths, found the two performing about the same.
Where exactly do I measure my waist?
Find the bottom of your ribs and the top of your hips, and put the tape halfway between them, which for most people sits just above the navel. Breathe out normally before reading it. Do not pull the tape tight, and do not hold your stomach in. Measuring at the narrowest point or at the belt line both give a different number.
Does it work for children?
Yes, from age five, using the same 0.4, 0.5 and 0.6 thresholds for both sexes and all ethnicities. That is unusual and useful, because BMI in children needs age and sex percentile charts to mean anything at all.
What if my BMI is over 35?
Then this measurement is not the assessment to use. The guideline says so directly: at a BMI of 35 or above, central adiposity is assumed, and the ratio adds nothing to the picture. The conversation worth having at that point is a broader one than a tape measure.
What if my ratio is under 0.4?
That is below the band called healthy, and it is worth a word with a doctor if it was not deliberate. A very low ratio can simply mean a long torso or a small frame, and it can also mean unintentional weight loss, which is the version worth ruling out.
Written and checked by the AskDoc Medical Team under our Medical Director, MBBS. How we review. Health education, not medical advice.