Health & medical New Zealand
Waist to Height Ratio Calculator New Zealand
Waist-to-height ratio compares your waist with your height and is a simple check of where you carry weight. A waist below half your height is a common aim. Enter both in centimetres to see your ratio, the band it falls in and how your waist compares with the usual thresholds.
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Measure halfway between the bottom rib and the top of the hip bone, breathing out normally.
Waist-to-height ratio
—Band
—
Waist to aim below (half your height)
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Waist threshold: increased risk
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Waist threshold: high risk
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The working
A screening number, not a diagnosis. General information, not medical advice. Speak to a doctor about your own health and risk.
How do I calculate my waist-to-height ratio?
Divide your waist measurement by your height, both in the same units. A waist of 88 cm at 175 cm tall gives 0.50. Below 0.5 is the usual aim, 0.5 to 0.59 means an increased risk and 0.6 or more a high risk. It is a screening measure, not a diagnosis.
How to measure your waist
Stand upright, breathe out normally and place a tape measure halfway between the lowest rib and the top of the hip bone, usually around the belly button level. Keep the tape snug but not tight and parallel to the floor. Measure bare skin or thin clothing. Do not hold your breath or suck in your stomach, which gives a falsely low number.
What to do with the result
A ratio under 0.5 is a good sign. If yours is higher, small, steady changes such as more movement, fewer sugary drinks and less alcohol can bring it down, and a reduction in belly fat often comes before a change on the scales. See a doctor for a full check of blood pressure, blood sugar and cholesterol, which tell you far more than any single measurement.
To see your BMI too, use the BMI calculator.
How this is calculated
The rule, step by step, so you can check any figure by hand.
ratio = waist ÷ height, in the same unitsunder 0.4: low, check you are not underweight; 0.4 to 0.49: healthy range0.5 to 0.59: increased risk; 0.6 and over: high riskwaist thresholds: increased risk from 94 cm (men) or 80 cm (women); high risk from 102 cm (men) or 88 cm (women)
Fat around the waist, particularly deep belly fat, is linked to type 2 diabetes, heart disease and some cancers, even in people whose weight looks normal. Waist-to-height ratio picks that up, and unlike BMI it does not need adjusting for adult height or sex, which is why many health bodies use it as a simple screening tool.
The waist thresholds in centimetres are the ones widely used by heart health groups. They apply to adults and are guides for talking to a doctor. Muscle, bone structure and ethnicity affect the numbers, and some groups carry risk at lower waist measurements.
A worked example
A man with a waist of 88 cm and a height of 175 cm.
- Ratio0.50
- Band0.5 to 0.59: increased risk
- Half his height87.5 cm
- Waist threshold94 cm increased, 102 cm high
A ratio of 0.50.
Losing about 4 cm would take the ratio under 0.5.
Adults only
The ratio and the waist thresholds are for adults. Children's measurements need growth charts and advice from a health professional.
What it leaves out
Body build, muscle mass, age and ethnicity are not modelled. A health professional will weigh these along with other tests.
What this calculator does not do
- Adults only
- Screening, not diagnosis
- Waist measured halfway between rib and hip
- Not medical advice
Common questions
What is a healthy waist-to-height ratio?
Under 0.5 is the usual aim, with 0.4 to 0.49 the healthy range.
Why is it used instead of BMI?
It reflects belly fat and needs no adjustment for height or sex.
How do I measure my waist?
Halfway between the bottom rib and the top of the hip bone, after breathing out.
What waist size is a risk?
From 94 cm for men and 80 cm for women.
Can I use it for children?
No. Ask a health professional.
Where these numbers come from
- Heart Foundation New Zealand Waist measurement guidance for heart health
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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