Waist-to-height, waist circumference and waist-to-hip: how the three measures differ
The waist and hip calculator gives three numbers: waist-to-height ratio, waist circumference and, if you enter hips, waist-to-hip ratio. The main cut-off is 0.5. Under NICE guidance (UK, January 2025) a waist-to-height ratio of 0.5 to 0.59 signals increased health risk and 0.6 or more a further increased risk. The three measures come from different scales, so one person can get different answers from them.
What the calculator computes
All three measures come from two or three tape measurements: height, waist and, optionally, hips.
| Measure | How it is computed | Cut-off | Whose scale |
|---|---|---|---|
| Waist-to-height ratio | waist / height, both in centimeters | 0.4-0.49: no increased risk; 0.5-0.59: increased; 0.6 or more: high | NICE |
| Waist circumference | the measurement itself, in centimeters | men: over 94 cm increased, over 102 cm substantially increased; women: over 80 and over 88 cm | WHO |
| Waist-to-hip ratio | waist / hips | substantially increased risk at 0.90 or more in men, 0.85 or more in women | WHO |
For a waist-to-height ratio below 0.4 the NICE scale sets no category, and the calculator gives no rating. "Risk" in these scales means the likelihood of hypertension, type 2 diabetes and cardiovascular disease linked to belly fat. It is not a forecast for an individual.
Where the cut-offs come from
NICE. The NG246 guideline on overweight and obesity management (14 January 2025) advises assessing waist-to-height ratio alongside BMI in adults with a BMI below 35. According to the text of the recommendation, the classification can be used for both sexes and all ethnic groups, including adults with high muscle mass.
Meta-analysis. The basis is the paper by Ashwell, Gunn and Gibson (Obesity Reviews, 2012): 31 studies, more than 300,000 adults from several ethnic groups. The authors compared how well each measure separates people with hypertension, type 2 diabetes, dyslipidaemia, metabolic syndrome and cardiovascular outcomes. Compared with BMI, waist-to-height ratio improved discrimination by 4 to 5% and waist circumference by 3%. For diabetes, hypertension and cardiovascular outcomes, waist-to-height ratio was significantly better than waist circumference too. This is a screening result: the measure picks out people who should have blood pressure, glucose and lipids checked. It does not predict disease.
WHO. The cut-offs for waist circumference and waist-to-hip ratio come from the report of the WHO expert consultation held in December 2008 (the report was published in 2011). It also sets out the measuring procedure described below.
One person, three answers
The three scales do not agree. Two examples worked out by the calculator's rules:
| Data | Waist-to-height | Waist circumference | Waist-to-hip |
|---|---|---|---|
| Woman, 170 cm, waist 82 cm, hips 98 cm | 0.48: no increased risk | over 80 cm: increased | 0.84: below the 0.85 cut-off |
| Man, 180 cm, waist 92 cm, hips 100 cm | 0.51: increased | under 94 cm: cut-off not exceeded | 0.92: substantially increased |
The disagreement is not a calculator error. The scales were built on different samples for different purposes, and none is declared the master of the others. The WHO report rates abdominal fat measures in general as better than BMI or at least as good, and says practical considerations favor the waist alone without hips. The meta-analysis above puts waist-to-height first. When answers differ, that is a reason to check blood pressure, glucose and lipids, not to pick the comfortable one.
What 0.5 means in centimeters
A cut-off expressed as a fraction of height gives a different waist in centimeters:
| Height | Waist at a ratio of 0.5 |
|---|---|
| 150 cm | 75 cm |
| 160 cm | 80 cm |
| 170 cm | 85 cm |
| 180 cm | 90 cm |
| 190 cm | 95 cm |
For shorter people the height-based cut-off is stricter than the fixed 80 cm for women and 94 cm for men; for taller people it is comparable or more lenient. That is the point of the measure: it needs no separate tables by height. The calculator compares the number rounded to two decimals, so it already shows 0.495 as 0.50. At a height of 170 cm the boundary falls at about 84 cm.
Where the cut-offs go wrong
- Different populations. WHO writes that the common waist circumference cut-offs rest mainly on data from people of European origin. In Asian populations metabolic risk rises at a smaller waist: the report cites International Diabetes Federation values of over 90 cm for men and over 80 cm for women. For several other groups there is too little data to name cut-offs. NICE, for its part, considers its waist-to-height scale usable across all ethnic groups.
- Age and low BMI. According to the WHO report, waist circumference and waist-to-hip ratio predict risk better in young and middle-aged adults than in older people and people with a low BMI. With age, fat shifts toward the visceral depot and muscle mass declines, and the waist grows.
- BMI of 35 or more. The NICE recommendation on waist-to-height ratio applies to adults with a BMI below 35.
- Pregnancy and under 18. The NICE guideline does not cover pregnancy. The calculator's cut-offs were derived for adults and are not applied in pregnancy.
- Where you measure. The WHO protocol: midway between the lower margin of the last palpable rib and the top of the iliac crest, at the end of a normal breath out, tape parallel to the floor. The measurement is repeated twice and averaged if the two differ by no more than 1 cm. At a height of 170 cm, one centimeter of waist moves the ratio by about 0.006, which is enough to cross a cut-off.
- A tape cannot tell fat types apart. It does not separate subcutaneous from visceral fat. How visceral fat differs is covered in the article on visceral fat. The WHO report says that combining BMI with waist measures may improve how well risk is discriminated and that having both is desirable (more on BMI).
How to use the result
Measure the waist at the end of a breath out, with the same tape, at the same point, preferably twice. Compare records made under similar conditions. If weight and waist move in different directions, that is common; see when the scale stays put but the waist shrinks. If you want body fat rather than risk, a different formula computes it: body fat from tape measurements.
You do not have to measure yourself. If the numbers cause anxiety or take up a lot of your thoughts, that is also a reason to talk to a doctor.
When to see a doctor
According to NICE, when a measurement points to increased risk, an adult is advised to seek advice and further assessment from a healthcare professional, for example an assessment of cardiometabolic risk factors. In practice that means blood pressure, blood glucose and a lipid profile. A ratio of 0.5 or more, a waist above the WHO cut-off, or a waist-to-hip ratio above its cut-off is a reason for that conversation, not a diagnosis. See a doctor also if the abdomen grows quickly for no clear reason, or if swelling or breathlessness appear.
The calculator is on the waist and hip calculator page.
Frequently asked questions
- What waist-to-height ratio signals increased risk?
- Under NICE (NG246, 2025): 0.4-0.49 means no increased risk, 0.5-0.59 increased, 0.6 or more high. The classification is for adults with a BMI below 35, of both sexes and all ethnic groups.
- Why is waist-to-height ratio better than BMI?
- In a meta-analysis of 31 studies (over 300,000 adults) it improved discrimination by 4 to 5% over BMI when separating people with hypertension, type 2 diabetes, dyslipidaemia and cardiovascular outcomes. BMI does not account for where fat sits.
- Why do the three measures give different answers?
- The scales were derived on different samples: waist-to-height from the NICE guideline, waist circumference and waist-to-hip from a WHO report. For example, a woman 170 cm tall with a waist of 82 cm and hips of 98 cm gets 0.48 (no increased risk) but is over 80 cm by WHO (increased).
- What are the WHO waist circumference cut-offs?
- Risk of metabolic complications is increased at a waist over 94 cm in men and over 80 cm in women, and substantially increased over 102 and over 88 cm. Waist-to-hip ratio: 0.90 or more in men, 0.85 or more in women.
- How do I measure my waist correctly?
- By the WHO protocol: standing, at the end of a normal breath out, tape parallel to the floor, midway between the lower margin of the last rib and the top of the iliac crest. Measure twice, and measure again if the two differ by more than 1 cm.
Read next
- Visceral fat: why it matters and how to measure it — Two people at the same weight, with the same BMI, can carry very different metabolic risk.
- Body mass index: how to calculate it and where it goes wrong — Body mass index takes ten seconds to calculate and is therefore used where it shouldn't be: for an individual.
- The scale is steady but your waist is shrinking: what it means — If your weight is steady but your waist measures smaller, change may be happening without a visible shift on the scale.
- Excess weight and health: what risks are confirmed — This topic is usually presented in a way meant to induce fear.
- Body fat from tape measurements: how the US Navy formula works and how far to trust it — The body fat calculator uses the Hodgdon and Beckett formula (US Navy, 1984): height plus neck and waist measurements and, for women, hips.
This article is for general information. It is not medical advice, a diagnosis, or a prescription for treatment or a diet, and it does not replace a consultation with your doctor. If you have a health condition, are pregnant, take medication, or follow a diet prescribed to you, decisions about food belong with your doctor.
Figures from regulations, guidelines and studies are given as they stood when this article was prepared and may since have changed; check them against the primary sources. This article is not advertising, an offer, or individual advice, and neither the author nor the site owner is responsible for decisions taken on the basis of it.