BodyCalWhat this waist-to-height ratio calculator does
Enter your height and waist measurement and you instantly get your waist-to-height ratio (WHtR), your health-risk category, the largest waist that keeps you in the healthy range for your height, and an animated scale showing exactly where you sit. Metric and imperial are one tap apart, so there's no conversion to do by hand.
The simple rule: keep your waist under half your height
The whole method fits in one sentence — your waist should be less than half your height. That's a ratio under 0.5, and it holds true for men and women of every height and ethnicity, which is part of why researchers love it. No lookup tables, no age-and-sex charts — just one number you can check with a tape measure.
- Below 0.4 — Possibly underweight
- 0.4 – 0.5 — Healthy
- 0.5 – 0.6 — Increased risk
- 0.6 and above — High to very high risk
Why it beats BMI for health risk
BMI has one big blind spot: it only knows your total weight, not where your fat is stored. Two people with an identical BMI can have completely different risk profiles if one carries fat around the hips and the other around the belly. Abdominal (visceral) fat — the fat packed around your organs — is the metabolically dangerous kind, driving insulin resistance, high blood pressure, and heart disease.
Because waist-to-height ratio measures your midsection directly, it captures that hidden risk. A landmark 2012 meta-analysis found WHtR predicted cardiometabolic risk factors better than both waist circumference and BMI, and UK NICE guidance now recommends checking it alongside BMI. If you've ever had a "healthy" BMI that didn't match how you felt, this is the number that often explains it.
A worked example
Someone 172 cm tall with an 84 cm waist has a ratio of 84 ÷ 172 = 0.49 — just inside the healthy range. For that height, the healthy limit is a waist of about 86 cm (34 in), which the calculator shows automatically. Add a few centimetres to the waist and the same person crosses into the increased-risk band — a reminder of how sensitive the midsection is.
How to measure your waist correctly
- Find the narrowest part of your torso, roughly level with your belly button and below your ribs.
- Keep the tape level and snug but not digging into the skin.
- Stand relaxed and breathe out normally before reading — no sucking in.
- Measure against bare skin or a thin layer, not over bulky clothing.
What to do with your result
If your ratio has crept above 0.5, the good news is that abdominal fat is often the first fat to respond to a calorie deficit and regular movement. Turn your goal into a daily target with our calorie deficit calculator, confirm you're losing fat rather than muscle with the body fat calculator, and cross-check the fuller picture with your BMI. Daily steps are one of the most effective ways to trim visceral fat specifically — find your target with the steps calculator.