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Waist-to-Height Ratio Calculator
Enter your waist and height in the same units to get your waist-to-height ratio (WHtR), the band it falls in, and the waist measurement that would put you at the widely used 0.5 mark.
What the ratio measures
The waist-to-height ratio divides your waist circumference by your height, using the same unit for both. Because the units cancel, the result is the same in centimetres or inches. The idea is that a healthy waist scales with the body: a taller person can carry a larger waist than a shorter person with the same risk. The popular summary is "keep your waist to less than half your height", which is a ratio below 0.5.
Waist size is used because fat stored around the abdominal organs, called central or visceral fat, is more closely linked to type 2 diabetes, high blood pressure and heart disease than fat stored on the hips and thighs. Overall weight and BMI cannot tell these patterns apart.
The bands
| WHtR | Meaning |
|---|---|
| Under 0.4 | Low; may suggest being underweight if other signs are present |
| 0.4 to 0.49 | Healthy range |
| 0.5 to 0.59 | Increased risk |
| 0.6 and above | High risk |
These cut-offs follow the UK NICE obesity guidance and the research by Ashwell and colleagues on the half-height rule. Different countries and research groups use slightly different thresholds, and risk rises smoothly rather than jumping at a line. A ratio of 0.49 is not very different from 0.50.
Measuring accurately
- Stand upright, relaxed, and breathe out normally.
- Place a flexible tape midway between the bottom of the ribs and the top of the hip bone, level all the way round.
- Keep the tape snug but not compressing the skin, and read it to the nearest millimetre.
- Measure height without shoes against a wall.
- Repeat twice and use the average. Clothing, a full stomach and the time of day can each shift the waist by a centimetre or two.
Waist measurements taken over clothing or at the navel give different results than the midpoint method, so keep the method the same when tracking change.
Limits
The ratio is a screening aid. It does not diagnose obesity, diabetes or heart disease, and it was developed mainly for adults. Children use age-specific charts. Pregnancy, abdominal swelling or a medical condition that causes fluid in the abdomen make the measurement meaningless. Very muscular people and people with short stature may sit slightly outside typical patterns. Pair it with blood pressure, blood tests and a talk with your clinician. This page is educational and not medical advice. See also the waist-to-hip ratio calculator for a different view of fat distribution.
Worked example
A person 170 cm tall measures a 94 cm waist.
Inputs
| Units | Centimetres |
|---|---|
| Waist circumference | 94 |
| Height | 170 |
Result
Increased health risk from central fat; the NICE obesity guideline calls this increased risk.
| Waist-to-height ratio | 0.553 |
|---|---|
| Band | 0.5 to 0.59 |
| Waist at a ratio of 0.5 | 85.0 cm |
| Waist at a ratio of 0.4 | 68.0 cm |
| Difference from the half-height mark | +9.0 cm |
Medical disclaimer: This tool is for education and general planning. It is not medical advice and does not diagnose any condition. If you are pregnant, under 18, have an eating-disorder history or a medical condition, speak to a doctor or registered dietitian before changing your diet or exercise.
Frequently asked questions
What is a good waist-to-height ratio?
A ratio from 0.4 to 0.49 is generally regarded as healthy, and keeping your waist below half your height is the simple rule. Ratios of 0.5 and above show increased risk, and 0.6 or more is high risk.
How do I calculate my waist-to-height ratio?
Divide your waist circumference by your height using the same unit. For example, an 85 cm waist and a 170 cm height give 85 divided by 170, which is 0.5.
Is waist-to-height ratio better than BMI?
It captures where fat is stored, which BMI ignores, and research suggests it may predict some cardiometabolic risks as well or better. Neither measure is a diagnosis, so using both gives a fuller picture.
Does the ratio work for all ages?
The adult cut-offs are mainly meant for adults. Children and teens are assessed differently, and older adults may be advised individually, so ask a health professional.
Should I measure at my belly button?
The usual method uses the midpoint between the lowest rib and the top of the hip bone, which is often a little above the navel. Whichever you pick, use the same spot each time.
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References and sources
- National Institute for Health and Care Excellence (NICE), guidance on overweight and obesity management, including waist-to-height ratio. Link
- Ashwell M, Gunn P, Gibson S (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. Obesity Reviews 13(3):275-286.