Calculate your waist-to-height ratio (WHtR) and assess your cardiovascular health risk. A ratio under 0.5 is healthy for adults of any height. Enter measurements in cm or inches.
These thresholds apply to all adults regardless of sex, age, or ethnicity — making WHtR a universal screening tool.
Waist-to-height ratio (WHtR) is a simple measure of body fat distribution, calculated by dividing waist circumference by height. Both measurements must be in the same unit. The result is a dimensionless number between approximately 0.3 and 0.7 for most adults.
The key threshold — and the reason WHtR has become clinically popular — is the simple rule of thumb: "Keep your waist to less than half your height." This translates to a WHtR below 0.5 for a healthy result. A 6-foot (183 cm) person should ideally have a waist below 91.5 cm (36 inches). A 5'4" (163 cm) person should ideally have a waist below 81.5 cm (32 inches).
The elegance of WHtR is that it accounts for body size. A waist of 90 cm means something very different on a person who is 6'4" (193 cm) tall than it does on a person who is 5'2" (157 cm) tall. BMI accounts for height through its weight-to-height-squared formula, but does not distinguish where body fat is stored. WHtR specifically captures central adiposity — the dangerous accumulation of fat around the abdomen.
Research published in the Annals of Human Biology by Margaret Ashwell and colleagues demonstrated that WHtR is a stronger predictor of cardiometabolic risk than BMI across multiple ethnic groups and both sexes. The universal threshold of 0.5 has been validated in studies across diverse populations globally.
The NHS now recommends using waist circumference alongside BMI for risk assessment, recognising that neither measure alone provides a complete picture. Using WHtR and BMI together provides the most comprehensive non-invasive assessment of health risk.
The NHS uses absolute waist circumference thresholds alongside WHtR for health risk assessment. These thresholds are based on the European background population; lower thresholds apply to people of South Asian, Chinese, and Japanese descent:
| Group | Increased Risk | High Risk |
|---|---|---|
| Men | Over 94 cm (37 inches) | Over 102 cm (40 inches) |
| Women | Over 80 cm (31.5 inches) | Over 88 cm (34.5 inches) |
| South Asian / Chinese men | Over 90 cm (35.5 inches) | Over 90 cm (high risk threshold) |
| South Asian / Chinese women | Over 80 cm (31.5 inches) | Over 80 cm (high risk threshold) |
These absolute thresholds complement the WHtR ratio. You can have a waist measurement below the NHS threshold but a WHtR above 0.5 if you are short-statured, or vice versa. Using both provides a more nuanced assessment.
Accurate waist measurement is critical for meaningful WHtR calculation. The NHS recommends:
1. Find the midpoint between your lowest rib and the top of your hip bone (iliac crest). This is typically at or just above navel level.
2. Wrap a flexible tape measure around your bare waist at this midpoint, keeping it horizontal and flat against the skin.
3. Stand relaxed. Do not hold your breath, pull in your stomach, or suck in your belly.
4. Breathe out gently, then take the measurement. The tape should be snug but not compressing the skin.
5. Repeat twice and use the average of the two measurements.
Waist circumference naturally increases slightly after meals; for consistency, measure first thing in the morning or before meals.
The reason waist circumference matters so much is visceral fat — the fat stored inside the abdominal cavity, surrounding organs including the liver, pancreas, intestines, and kidneys. Unlike subcutaneous fat (the fat you can pinch just under the skin), visceral fat is highly metabolically active.
Visceral fat releases inflammatory cytokines and free fatty acids directly into the portal vein, which carries blood to the liver. This promotes liver fat accumulation, insulin resistance, and systemic inflammation — the physiological precursors to type 2 diabetes, cardiovascular disease, stroke, and certain cancers including colorectal and postmenopausal breast cancer.
You cannot directly measure visceral fat without imaging (MRI or CT scan), but waist circumference and WHtR are the best non-invasive proxies for visceral fat accumulation. This is why these measurements have proven to be stronger risk predictors than BMI in large epidemiological studies.
Aerobic exercise: Regular aerobic exercise — particularly 150-300 minutes per week of moderate intensity (Zone 2 heart rate training) — is the most effective intervention for reducing visceral fat. Studies show that aerobic exercise preferentially reduces visceral fat even before significant changes in body weight occur.
Caloric deficit: Sustained modest caloric restriction (500-750 kcal below maintenance) combined with exercise produces the best long-term results. Very low calorie diets without exercise cause muscle loss alongside fat loss.
Sleep: Poor sleep quality and insufficient sleep (under 7 hours per night) is strongly associated with increased visceral fat accumulation. Prioritising sleep quality has measurable benefits on body composition.
Reducing ultra-processed foods: Diets high in ultra-processed foods are independently associated with greater visceral fat accumulation. Replacing processed foods with whole foods, vegetables, lean protein, and healthy fats reduces visceral fat beyond what calories alone would predict.
Stress management: Chronic stress elevates cortisol, which promotes visceral fat storage specifically. Stress reduction strategies (exercise, sleep, mindfulness, social connection) complement dietary and exercise interventions.
| Height | Max Healthy Waist (WHtR 0.5) | Overweight Waist (WHtR 0.6) |
|---|---|---|
| 5'0" (152 cm) | 76 cm (30 in) | 91 cm (36 in) |
| 5'2" (157 cm) | 79 cm (31 in) | 94 cm (37 in) |
| 5'4" (163 cm) | 82 cm (32 in) | 98 cm (38.5 in) |
| 5'6" (168 cm) | 84 cm (33 in) | 101 cm (40 in) |
| 5'8" (173 cm) | 87 cm (34 in) | 104 cm (41 in) |
| 5'10" (178 cm) | 89 cm (35 in) | 107 cm (42 in) |
| 6'0" (183 cm) | 92 cm (36 in) | 110 cm (43 in) |
| 6'2" (188 cm) | 94 cm (37 in) | 113 cm (44.5 in) |