Waist to Hip Ratio Calculator
This waist to hip ratio calculator divides your waist measurement by your hip measurement and compares the result with the cut-offs from a World Health Organization expert consultation. It also checks your waist size on its own against the NIH’s guidance and, if you add your height, works out your waist-to-height ratio. All three look at where you carry fat, which BMI alone does not show.
Updated
Results
- WHO cut-off for your sex
- Waist vs NIH threshold
- NIH waist thresholdRisk rises above this size
- Waist-to-height ratioShown when you enter height
- Waist-to-height category (NICE)Adults with BMI under 35
Results are estimates. See the methodology below.
How to use the calculator
- Choose inches or centimeters, and select your sex.
- Enter your waist and hip measurements.
- Optionally, enter your height in the same unit to see your waist-to-height ratio and its category. These two results only appear when height is filled in.
- Read your ratio, how it compares with the WHO cut-off for your sex, and whether your waist is above the NIH threshold.
How to measure
- Waist: stand up, find the bottom of your ribs and the top of your hip bones, and wrap the tape around your middle midway between them. Read it after breathing out normally.
- Hips: measure around the widest part of your buttocks.
- Keep the tape level and snug without pressing into the skin, and use the same unit for every measurement.
How it is calculated
Waist-to-hip ratio = waist ÷ hip, rounded to two decimals. The category is based on the rounded number, so the label always matches what you see.
| Measure | Men | Women | Reference |
|---|---|---|---|
| Waist-to-hip ratio | 0.90 | 0.85 | WHO expert consultation (2008) |
| Waist circumference | more than 40 in (101.6 cm) | more than 35 in (88.9 cm) | NIH, National Heart, Lung, and Blood Institute |
WHO links ratios at these cut-offs with a substantially increased risk of metabolic complications. Secondary sources differ on whether a ratio exactly at the cut-off counts; the calculator places it in that group. WHO gives one cut-off per sex, so there are no “low” or “moderate” bands. The NHLBI says a waist above its threshold increases the risk of heart disease and type 2 diabetes.
Waist-to-height ratio
Waist ÷ height, using the categories from the UK’s National Institute for Health and Care Excellence (NICE), for adults with a BMI under 35 of both sexes and all ethnicities: 0.40–0.49 healthy central adiposity, 0.50–0.59 increased, and 0.60 or more high. Below 0.40, NICE gives no category, so the calculator shows it as not classified.
Examples
Woman, waist 32 in, hips 40 in
32 ÷ 40 = 0.80, below the WHO cut-off of 0.85. Her waist is not above the NIH threshold of 35 in.
Woman, waist 34 in, hips 40 in
The ratio is exactly 0.85, so the calculator shows substantially increased risk, even though her waist is still under 35 in. The two measures can tell different stories.
Man, waist 38 in, hips 40 in, height 70 in
His ratio is 0.95, above the 0.90 cut-off for men, while his waist is under the 40-inch threshold. His waist-to-height ratio is 0.54, in NICE’s increased range.
How to read the result
A ratio above the cut-off is a signal worth discussing with a doctor, not a diagnosis. These are population screening tools: they don’t account for age, ethnicity, pregnancy or body build, and small measuring errors can move you across a line. Measure two or three times and use the average.
Results are not meaningful during pregnancy and are designed for adults. If your numbers concern you, a healthcare provider can look at them together with your blood pressure, blood sugar, cholesterol and family history.
Frequently asked questions
What is a good waist to hip ratio?
WHO’s cut-offs are 0.90 for men and 0.85 for women. A ratio below them is outside the substantially increased risk group in that report. A lower ratio is not a full health check, so read it alongside your waist size and other results.
Why does waist size matter more than weight?
Fat stored around the abdomen is linked with a higher risk of heart disease and type 2 diabetes. BMI uses only height and weight, so it can’t tell where the fat is.
Is waist-to-height ratio better than waist-to-hip ratio?
They measure different things. NICE in the UK recommends waist-to-height ratio for adults with a BMI under 35, with a simple message: keep your waist to less than half your height. This calculator shows both so you can compare.
Where exactly should I measure my waist?
Midway between the bottom of your ribs and the top of your hip bones, just after breathing out. The NHLBI’s instructions place the tape just above the hip bones.
Do the cut-offs differ for different ethnic groups?
This calculator uses the same WHO and NIH thresholds for everyone and does not apply ethnicity-specific cut-offs. NICE states that its waist-to-height categories apply to all ethnicities.
Can I use it during pregnancy or for children?
No. Waist measurements change during pregnancy, and the thresholds here are for adults. A doctor or pediatrician can advise instead.
Sources
- World Health Organization — Waist circumference and waist-hip ratio: report of a WHO expert consultation (Geneva, 8–11 December 2008)
- NIH, National Heart, Lung, and Blood Institute — Assessing Your Weight and Health Risk
- NICE guideline NG246 — Identifying and assessing overweight, obesity and central adiposity
This calculator is a screening estimate for adults, not a diagnosis or medical advice. Talk to your doctor about what your measurements mean for your health.