How this waist to height ratio calculator works
The math is simple. We divide your waist size by your height, using the same units for both.
Waist to height ratio = waist ÷ height
For example, if you are 5 ft 6 in (66 in, or 168 cm) tall and your waist is 32 in (81 cm), your ratio is 32 ÷ 66 = 0.48.
The calculator also shows the waist size that equals half your height. For someone who is 5 ft 6 in (168 cm), that is 33 in (84 cm). Keep your waist below that number to stay under 0.5.
What your result means
We use the bands from the 2025 NICE guideline on overweight and obesity:
| Ratio | What it means |
|---|---|
| Under 0.5 | Healthy. Your waist is less than half your height. |
| 0.5 to 0.59 | Increased central fat, with increased health risks |
| 0.6 or more | High central fat, with further increased health risks |
Fat around your middle is linked to health problems such as type 2 diabetes and heart disease. That is why waist size can tell you something your weight alone cannot.
NICE says the ratio can be used for adults with a BMI under 35. It works for both sexes and all ethnic groups, and for people with a lot of muscle, whose BMI can look high even when they are lean.
How to measure your waist
- Stand up straight with your feet together.
- Breathe out normally. Do not suck in.
- Find the spot halfway between your lowest rib and the top of your hip bone.
- Wrap a tape measure around that spot. Keep it level and snug, but not tight.
Measure at the same time of day each time, like first thing in the morning.
If your ratio is 0.5 or higher
Small changes add up. Eating enough protein and fiber, cutting back on added sugar, and moving more can all help. Try our calorie deficit calculator to set a gentle calorie target. You can also compare your result with our waist to hip ratio calculator.
For more on what the ratio means, read our waist to height ratio guide. If your ratio is 0.6 or more, consider talking to your doctor.
This calculator is for adults. If you are under 18 or pregnant, ask your doctor how to check your health instead.