What are the WHO risk category thresholds?

According to the World Health Organization: For men, WHR <0.90 is low risk, 0.90–0.99 is moderate risk, and ≥1.00 is high risk. For women, WHR <0.80 is low risk, 0.80–0.85 is moderate risk, and ≥0.86 is high risk.

How do I measure my waist correctly?

Stand relaxed (not sucking in your stomach). Measure the narrowest point of your waist, usually about 2 cm above your navel. Keep the tape measure parallel to the floor and snug but not tight. Take the measurement at the end of a normal breath out.

How do I measure my hips correctly?

Stand with feet together. Measure the widest part of your hips and buttocks, keeping the tape measure horizontal and parallel to the floor. This is typically at the level of the greater trochanters (the bony protrusions on the sides of your hips).

Waist-to-Hip Ratio Calculator

While BMI gets most of the attention in health discussions, research increasingly shows that where you store fat matters as much as how much you carry. The waist-to-hip ratio (WHR) is a simple, evidence-based measure of fat distribution that helps predict your risk of heart disease, type 2 diabetes, and other metabolic conditions — often better than BMI alone.

What Is the Waist-to-Hip Ratio?

The waist-to-hip ratio is calculated by dividing your waist circumference by your hip circumference, measured in the same units:

WHR = Waist circumference ÷ Hip circumference

A person with a 80 cm waist and 100 cm hips has a WHR of 0.80.

The WHR measures body fat distribution, specifically how much fat is stored centrally (around the abdomen) relative to peripherally (around the hips and thighs). Central (abdominal) fat, also known as visceral fat, is metabolically much more dangerous than subcutaneous fat stored at the hips and thighs.

Why Abdominal Fat Is Dangerous

Visceral fat wraps around internal organs including the liver, pancreas, and kidneys. Unlike subcutaneous fat, it is hormonally active and releases inflammatory cytokines and free fatty acids directly into the portal circulation. This contributes to:

Insulin resistance and type 2 diabetes
Elevated blood pressure
Dyslipidaemia (abnormal cholesterol levels)
Increased cardiovascular risk
Non-alcoholic fatty liver disease

WHO Risk Category Classifications

The World Health Organization established the following WHR thresholds (WHO Technical Report 894, 2000):

Males:

WHR < 0.90: Low risk
WHR 0.90–0.99: Moderate risk
WHR ≥ 1.00: High risk

Females:

WHR < 0.80: Low risk
WHR 0.80–0.85: Moderate risk
WHR ≥ 0.86: High risk

Central Obesity Thresholds (Absolute Waist Circumference)

In addition to WHR, the WHO identifies central obesity by waist circumference alone:

Males: waist ≥ 102 cm (≥ 40 inches)
Females: waist ≥ 88 cm (≥ 35 inches)

How to Measure Correctly

Waist Measurement

Stand relaxed with feet together, do not hold your breath or pull in your stomach.
Locate the narrowest point of your torso — typically about 2 cm above the navel (belly button).
Place the measuring tape horizontally around your waist at this level.
The tape should be snug but not compressing the skin.
Read the measurement at the end of a normal exhalation.

Hip Measurement

Stand with feet together.
Locate the widest point of your hips and buttocks — typically at the level of the greater trochanters (the bony prominences on the outer sides of your upper legs).
Place the measuring tape horizontally at this level.
Keep the tape parallel to the floor.
Read the measurement while standing normally.

Examples

Example 1: Male, Low Risk

Waist: 82 cm, Hip: 98 cm
WHR = 82 ÷ 98 = 0.84 → Low risk
Waist 82 cm < 102 cm threshold → No central obesity

Example 2: Male, Moderate Risk

Waist: 94 cm, Hip: 100 cm
WHR = 94 ÷ 100 = 0.94 → Moderate risk
Waist 94 cm < 102 cm → No central obesity flag

Example 3: Female, High Risk

Waist: 91 cm, Hip: 102 cm
WHR = 91 ÷ 102 = 0.89 → High risk (≥ 0.86)
Waist 91 cm ≥ 88 cm → Central obesity risk present

Frequently Asked Questions

Is WHR better than BMI for assessing health risk? For predicting cardiovascular disease and type 2 diabetes, WHR has been shown to be a stronger predictor than BMI in several large studies, including the INTERHEART study (Yusuf et al., Lancet, 2004), which studied 27,098 participants across 52 countries. However, WHR and BMI measure different things. BMI reflects overall body mass; WHR reflects fat distribution. Using both together provides the most comprehensive picture.

Can a person have a healthy BMI but an unhealthy WHR? Yes. This is sometimes called the “normal weight obese” or “metabolically obese normal weight” (MONW) phenomenon. A person of normal BMI can still have excess visceral fat, leading to an elevated WHR and associated metabolic risks. This is one reason why WHR is a valuable supplementary measure.

Does ethnicity affect the thresholds? Yes. Research suggests that people of Asian ancestry tend to accumulate visceral fat at lower BMI and waist values than European populations. Some health authorities recommend lower waist circumference thresholds for Asian populations (e.g., ≥90 cm for Asian males, ≥80 cm for Asian females for central obesity). Consult local health guidelines.

Can exercise improve my WHR? Yes. Aerobic exercise and strength training both help reduce visceral fat, which preferentially mobilises in response to physical activity. Diet changes (reducing refined carbohydrates and added sugars) also specifically reduce abdominal fat stores. In general, waist circumference reduces before hip circumference during a weight loss programme, which often temporarily worsens WHR before it improves.

How often should I check my WHR? For most healthy adults, checking every 3–6 months during a weight management programme, or annually as a routine health check, is sufficient. Measurement variability between readings can be reduced by measuring at the same time of day, on the same scale, under the same conditions.