Waist-to-Height Ratio Calculator
Divide waist circumference by height to obtain a waist-to-height ratio.
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What this calculator estimates
Divide waist circumference by height to obtain a waist-to-height ratio. The result is a broad indicator of central body size, not a direct measure of body fat or a diagnosis.
Inputs and calculation method
Enter waist and height in centimetres. The tool divides waist by height and displays the ratio to two decimal places, a broad label, and the waist measurement corresponding to a ratio of 0.5.
Formula and units
Waist-to-height ratio = waist ÷ height, using the same units. The 0.5 comparison waist = height × 0.5. Labels use the unrounded ratio: below 0.4, 0.4 to below 0.5, 0.5 to below 0.6, and 0.6 or higher.
How to use it
- Measure waist midway between the bottom of the ribs and top of the hips, after a natural breath out.
- Enter waist and height in cm.
- Calculate and read the ratio together with its broad category.
- Compare repeated measurements taken at the same location and under similar conditions.
Worked example
At a waist of 75 cm and height of 165 cm, the ratio is 75 ÷ 165 = 0.45 after rounding. The 0.5 comparison waist is 82.5 cm. At the same height, a 90 cm waist gives a ratio of 0.55.
How to read the result
NICE uses waist-to-height ratio alongside BMI in adults with BMI below 35. Ratios of 0.5 to 0.59 and 0.6 or above indicate increasing central adiposity in that context. The tool’s “Low” label below 0.4 is not a diagnosis or a recommendation to reduce waist size further.
Common mistakes
- Entering waist in inches and height in centimetres.
- Measuring a different part of the abdomen each time.
- Treating the displayed 0.5 comparison as an individually prescribed target.
Method limitations
The ratio does not assess pregnancy, growth, body-fat percentage or overall health. Tape placement and breathing affect the input; a rounded ratio near a boundary can conceal a small numerical difference.
Sources and method references
Supporting guides for this calculator
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Waist-to-Height Ratio Calculator FAQs
Does weight enter this calculation?
No. Only waist and height are used.
Can I use inches?
The displayed fields are labelled cm. The ratio is mathematically unchanged when both inputs use the same units, but the comparison waist is labelled cm, so enter centimetres.
Is a ratio below 0.5 proof of good health?
No. It is one screening indicator and does not rule out other health risks.
Using the estimate
Measure waist consistently and keep units aligned. Interpret the ratio as one indicator alongside relevant health information.