You want an adult central-adiposity screening reference that complements, but does not replace, BMI or clinical assessment.
Waist-to-Height Ratio Calculator
Calculate adult waist-to-height ratio with metric or US customary units and compare it with the half-your-height screening guideline.
Start here
Choose metric or US customary units.
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Your height and waist measurements are calculated locally in your browser and are not uploaded to a server.
Useful for
Compare waist circumference with height
Waist-to-height ratio0.47waist ÷ height
Screening guideBelow the half-height lineThe waist is less than half of height in this general adult screening measure.
Half of height34 inSimple 0.50 reference line
Ratio positionCurrent: 0.47
Below 0.400.40–0.490.50–0.590.60+
Half-your-height check
Your waist is 2.0 in below the half-height line.
Track consistently
Use the same tape position and similar conditions each time; the trend is more useful than a tiny one-off change.
General adult screening only; not a diagnosis or a tool for pregnancy or children.
Quick answer
Calculate adult waist-to-height ratio
Enter waist circumference and height in inches or centimeters to calculate waist ÷ height and compare the result with the simple half-your-height screening message.
Measurement location and technique matter, and the result is not a diagnosis or a universal cutoff for children, pregnancy, or every clinical situation.
BMI Calculator: Calculate adult body mass index from height and weight locally in your browser.
About this tool
Calculate adult waist-to-height ratio with metric or US customary units and compare it with the half-your-height screening guideline.
Your height and waist measurements are calculated locally in your browser and are not uploaded to a server.
Health information notice
This is a general adult screening estimate, not a diagnosis or individualized medical advice. It is not designed for pregnancy, children, or situations where a clinician recommends another measurement method.
How to use it
- Choose metric or US customary units.
- Enter adult height and waist circumference measured in the same unit.
- Calculate the ratio and review the measurement guidance and limitations.
Common use cases
- Compare waist circumference with height
- Track a simple adult central-adiposity screening measure
- Convert a measurement between inches and centimeters
- Use alongside BMI without treating either result as a diagnosis
Waist-to-Height Ratio Formula and Example
Use the same unit for both measurements: waist-to-height ratio = waist circumference ÷ height. A 32-inch waist and 68-inch height gives 32 ÷ 68 = 0.47.
NICE describes keeping waist size below half of height as a simple adult message for reducing health risk. That corresponds to a ratio below 0.5, but the result remains a screening measure rather than a diagnosis.
| Example | Calculation | Result |
|---|---|---|
| 32 in waist, 68 in height | 32 ÷ 68 | 0.47 |
| 84 cm waist, 175 cm height | 84 ÷ 175 | 0.48 |
| 90 cm waist, 170 cm height | 90 ÷ 170 | 0.53 |
Measure Consistently and Interpret Carefully
A small change in tape position, clothing, posture, breathing, or time of day can change the measurement. For tracking, use the same method and similar conditions each time rather than reacting to one reading.
- Keep the tape level and snug without compressing the skin.
- Use the waist landmark specified by the health guidance you are following.
- Discuss results with a qualified professional when health conditions, pregnancy, growth, medication, or symptoms affect interpretation.
FAQ
How is waist-to-height ratio calculated?
Divide waist circumference by height using the same unit for both values. For example, 32 inches divided by 68 inches is about 0.47.
What does half your height mean?
A ratio of 0.5 means the waist measurement equals half the person's height. NICE uses keeping the waist below half of height as a simple adult risk-reduction message.
Where should I measure my waist?
Use the measurement method required by the guidance you are following and keep it consistent over time. Common methods place the tape around the midpoint between the lowest rib and top of the hip bone.
Does this replace BMI or medical evaluation?
No. It can add information about central fat distribution, but health risk depends on many factors and should be interpreted with appropriate professional guidance.