Waist-to-Height Ratio Calculator
Compare your waist to your height — the simple “keep your waist under half your height” health check.
How it works
ratio = waist ÷ height (same units)
Waist-to-height ratio checks central fat against your frame with a single, easy rule of thumb: your waist should be less than half your height. Because it scales to height, it works across a wide range of body sizes and is often a better warning sign than BMI for belly fat. Under 0.5 is considered healthy; 0.5–0.6 signals increased risk and 0.6 or more high risk.
Worked example
A 34-inch waist at 69 inches tall: 34 ÷ 69 = 0.49 — just inside the healthy range, which tops out at 0.50 (a 34.5-inch waist for this height).
Frequently asked questions
Why is this better than BMI for some people?
BMI can’t tell muscle from belly fat. Waist-to-height focuses on the abdominal fat most tied to heart and metabolic risk, so a muscular person is less likely to be mislabeled.
Does the “half your height” rule work for kids?
It holds up reasonably well from about age six, which is part of its appeal, but children should be assessed with growth charts by a pediatrician.
Should I use inches or centimeters?
Either — since it’s a ratio, the units cancel out as long as you measure waist and height the same way.
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General educational estimate, not medical advice. Talk to a doctor for anything about your health.