Waist-to-Height Ratio Calculator

What your waist-to-height ratio tells you

Waist-to-height ratio (WHtR) is your waist circumference divided by your height. A result under 0.5 means your waist is less than half your height, which the UK National Institute for Health and Care Excellence (NICE) treats as the line between healthy and increased central fat.

The ratio targets central adiposity, the fat stored around the abdomen and organs. That fat is more closely tied to type 2 diabetes, high blood pressure, and heart disease than fat on the hips or thighs. BMI cannot see where fat sits, and waist size alone ignores height, so a 36 inch waist means something different at 5 ft 2 in than at 6 ft 3 in. Dividing by height fixes that with one step and no charts.

NICE added WHtR to its obesity guidance in 2022 and recommends it alongside BMI for adults with a BMI under 35.

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Healthy, increased, and high: the NICE bands

NICE uses three bands and applies them to men and women of all ethnicities, including adults with high muscle mass. The committee reviewed studies across ethnic groups and found that the best cut-off was generally around 0.5 for all of them. The 0.6 line marks a further step up in risk.

NICE sets no band below 0.4. A ratio that low usually reflects a small waist on a low body weight, so check it against your BMI.

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Healthy waist size by height

Your healthy waist limit is half your height. The table gives that limit and the 0.6 high-risk line for common heights, so you can check a tape reading without a calculator.

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How to measure your waist

Most errors come from the tape, not the math.

The World Health Organization protocol places the tape midway between the lowest rib you can feel and the top of the hip bone (iliac crest). Stand with feet close together, arms relaxed at your sides, and read the tape at the end of a normal breath out. Use a tape that does not stretch, keep it level all the way round, and pull it snug without pressing into the skin. Take two readings. If they are within 1 cm (about 0.4 in) of each other, use the average; if not, measure twice more.

Some surveys, including the US NHANES, measure at the top of the hip bone instead, and some people use the navel. Pick one site and keep it. Switching landmarks between checks can shift your ratio by a few hundredths, enough to cross a band boundary. Measure height barefoot against a wall rather than relying on a remembered figure.

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The formula and a worked example

WHtR = waist ÷ height. Both numbers must be in the same unit; the units cancel, so the ratio is the same in inches or centimeters.

Worked example: a woman is 5 ft 6 in (66 in, 167.6 cm) with a 35 inch (89 cm) waist. Her ratio is 35 ÷ 66 = 0.53, which falls in the increased band. Her healthy waist range is 0.4 × 66 = 26.4 in up to 0.5 × 66 = 33 in, so she is 2 inches above the 0.5 boundary. In centimeters the result matches: 89 ÷ 167.6 = 0.53.

The calculator shows the same four numbers: the ratio, the NICE band, your healthy waist range, and the distance to 0.5.

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How to use this calculator

Choose imperial or metric, enter your height, then your waist from the tape. Enter the average of your two readings.

The ratio appears with its NICE band. The healthy waist range tells you where 0.4 and 0.5 fall for your height, and the last line shows how far your waist is above or below 0.5. That last figure is the practical target, because height does not change and waist does.

For tracking, measure once a month at the same time of day, before eating.

Why waist-to-height beats BMI for central fat

A 2012 meta-analysis pooled 31 studies covering more than 300,000 adults from several ethnic groups. It ranked WHtR above waist circumference and BMI for picking out diabetes, high blood pressure, and cardiovascular disease in both sexes. WHtR improved discrimination by 4 to 5% over BMI, and it beat waist size alone for every outcome except metabolic syndrome in men. A 2010 systematic review from the same group proposed 0.5 as a boundary that works across populations.

The ratio also catches people BMI misses. In UK survey data from 1,453 adults, 35% of those judged at no increased risk by BMI and waist size had a WHtR of 0.5 or more, and the people with a healthy BMI but a high ratio had worse cardiometabolic risk factors.

In a DXA scan study of 81 adults, WHtR predicted both total body fat percentage and visceral fat mass better than BMI, waist size, or waist-to-hip ratio. Ratios of 0.53 in men and 0.54 in women matched obesity by body fat, and 0.59 matched high visceral fat. The prediction errors were still similar to skinfold methods, so the ratio screens; it does not measure fat.

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Waist-to-height ratio and life expectancy

Using 20-year follow-up of British adults, Ashwell and colleagues found WHtR predicted death better than BMI. Years of life lost rose steeply once the ratio passed about 0.52. A 30-year-old male non-smoker with a ratio of 0.7 was expected to live 7.2 years fewer than one at 0.5; for women, the gap between 0.7 and 0.46 was 4.6 years.

The advantage is real but modest. In US cohorts of 16,332 male physicians and 32,700 female health professionals, WHtR had the strongest link with heart attack, stroke, and cardiovascular death. Every measure of body size still predicted risk, and the authors judged the differences from BMI too small to matter much in the clinic.

The takeaway: a high ratio is a reason to act, and BMI and WHtR together tell you more than either alone.

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Waist-to-height ratio in children and teens

NICE applies the same three bands to children and young people aged 5 and over. Because the ratio already adjusts for height, it avoids the age and sex centile charts that BMI needs for children.

A 2021 meta-analysis of 41 studies in 138,561 children aged 3 to 18 found that cut-offs between 0.46 and 0.50 identified cardiometabolic risk with an accuracy score (AUC) of 0.83. The best cut-off varied by region: 0.46 worked better in East and Southeast Asia and 0.54 or higher in Latin America. A single 0.5 line is a sound screen, but a child near it deserves a look at the full picture with a doctor, especially around puberty when growth changes body shape quickly.

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Limits and when not to use it

WHtR is a screening measure. It cannot diagnose diabetes, hypertension, or heart disease, and it does not tell visceral fat apart from fat under the skin.

Skip it during pregnancy and for children under 5. NICE validated its adult bands only for people with a BMI under 35. Fluid in the abdomen, an enlarged liver or spleen, a hernia, or recent abdominal surgery will inflate the waist reading without meaning more fat. Bloating after a large meal also enlarges the reading, which is why a consistent time of day matters.

NICE uses one set of WHtR bands for everyone but lower BMI thresholds for people of South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean family background, who develop weight-related disease at a smaller body size. If that applies to you, check your BMI against the lower thresholds as well.

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What to do with a high result

First, measure again on another day with the same method. One reading near a boundary is not a trend.

If you are at 0.5 or above, ask for a blood pressure check and blood tests for glucose or HbA1c and cholesterol. These show whether the extra central fat is already affecting your health. At 0.6 or above, NICE describes the risk as further increased, so book that check soon rather than waiting for a routine visit. Central fat responds to a sustained calorie deficit and regular physical activity, and the waist gap in your result gives you a concrete number to work toward.

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How it works

WHtR = waist circumference ÷ height, both in the same unit, so the result has no unit. Categories follow NICE guideline NG246: 0.4 to 0.49 healthy, 0.5 to 0.59 increased, 0.6 or more high central adiposity. NICE applies these bands to both sexes and all ethnicities, for adults with a BMI under 35 and for children aged 5 and over. The healthy waist range is 0.4 × height up to 0.5 × height.

Frequently asked questions

• What is a good waist-to-height ratio?Between 0.40 and 0.49. NICE calls this healthy central adiposity, with no increased health risk from waist size. The simple rule is to keep your waist to less than half your height.
• Is waist-to-height ratio better than BMI?For spotting cardiometabolic risk, usually yes. A meta-analysis of more than 300,000 adults found that WHtR identified diabetes, high blood pressure, and heart disease better than BMI and better than waist size alone, in both men and women. NICE recommends using it alongside BMI, not in place of it.
• Can I have a healthy BMI and a high waist-to-height ratio?Yes. In a UK survey of 1,453 adults, 35% of people rated at no increased risk by BMI and waist size had a WHtR of 0.5 or more. Those with a healthy BMI but a ratio of 0.5 or more had worse cardiometabolic risk factors than those under 0.5.
• Is the 0.5 cut-off the same for men and women?Yes. NICE uses the same bands for both sexes and all ethnicities because the evidence it reviewed found cut-offs near 0.5 across groups. Dividing by height already adjusts for the fact that men and taller people tend to have larger waists.
• Does waist-to-height ratio work for children?NICE applies the same bands to children and young people aged 5 and over. A 2021 meta-analysis of 41 studies in 138,561 children found good accuracy for cut-offs between 0.46 and 0.50, though the best cut-off varied by region.
• Who should not use this calculator?It does not apply during pregnancy, to children under 5, or to adults with a BMI of 35 or more, because NICE validated its bands only below that BMI. Abdominal swelling from fluid, organ enlargement, or recent surgery also makes the ratio misleading.

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References

1. NICE, 2025. Overweight and obesity management (NG246): identifying and assessing overweight, obesity and central adiposity
2. Ashwell, Gunn & Gibson, Obesity Reviews 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
3. Browning, Hsieh & Ashwell, Nutrition Research Reviews 2010. A systematic review of waist-to-height ratio as a screening tool for the prediction of cardiovascular disease and diabetes: 0.5 could be a suitable global boundary value
4. Ashwell & Gibson, BMJ Open 2016. Waist-to-height ratio as an indicator of early health risk: simpler and more predictive than using a matrix based on BMI and waist circumference
5. Ashwell, Mayhew, Richardson & Rickayzen, PLoS One 2014. Waist-to-height ratio is more predictive of years of life lost than body mass index
6. Swainson et al., PLoS One 2017. Prediction of whole-body fat percentage and visceral adipose tissue mass from five anthropometric variables
7. Ezzatvar et al., Obesity Reviews 2021. Accuracy of different cutoffs of the waist-to-height ratio as a screening tool for cardiometabolic risk in children and adolescents: a systematic review and meta-analysis
8. WHO, 2008. Waist circumference and waist-hip ratio: report of a WHO expert consultation
9. Gelber et al., JACC 2008. Measures of obesity and cardiovascular risk among men and women