How to measure your waist-to-height ratio
- Find the spot. Find the midpoint between your lowest rib and the top of your hip bone, at the side of your body. It's usually around your belly button.
- Measure your waist. Stand up straight, breathe out normally and wrap a tape measure around your waist at that point, level all the way round and snug without pressing in.
- Divide by your height. Use the same units for both. An 80 cm waist at 170 cm tall is 80 ÷ 170 = 0.47.
- Compare with the categories. Under 0.5 is healthy in NICE's categories. Or simply check that your waist is less than half your height: under 85 cm at 170 cm, or under 34 inches at 5 ft 8 in.
How the waist-to-height ratio calculator works
- The ratio. Your waist divided by your height, in the same units, shown to two decimals.
- Your category. NICE’s adult boundaries, from its guideline on overweight and obesity management:
| Waist-to-height ratio | NICE category | What it means |
|---|---|---|
| 0.4 to 0.49 | Healthy central adiposity | No increased health risks |
| 0.5 to 0.59 | Increased central adiposity | Increased health risks |
| 0.6 or more | High central adiposity | Further increased health risks |
- Your waist target. Half your height: the waist that keeps your ratio under 0.5.
NICE uses these categories for adults with a BMI under 35, of both sexes and all ethnicities, including people with a lot of muscle. Below 0.4 isn’t one of NICE’s categories; the calculator simply shows it as below the healthy range.
Waist to stay under, by height
| Height | Keep your waist under |
|---|---|
| 5 ft 0 in (152 cm) | 30 in (76 cm) |
| 5 ft 4 in (163 cm) | 32 in (81 cm) |
| 5 ft 8 in (173 cm) | 34 in (86 cm) |
| 6 ft 0 in (183 cm) | 36 in (91 cm) |
| 6 ft 4 in (193 cm) | 38 in (97 cm) |
Why your waist matters
BMI compares weight with height, but it can’t see where your body carries fat. Fat stored around the abdomen is more closely linked to type 2 diabetes, high blood pressure and heart disease than fat elsewhere, which is why NICE recommends measuring waist-to-height ratio alongside BMI. The older NIH guidelines used fixed waist cut-offs instead (102 cm, or 40 inches, for men and 88 cm, or 35 inches, for women); a ratio adjusts for height, so the same rule works for a short person and a tall one.
Getting a reliable measurement
- Same spot, same time. Measure halfway between your lowest rib and the top of your hip bone, ideally in the morning before eating.
- Breathe out normally. Don’t hold your breath or pull your stomach in.
- Level tape. Keep it horizontal all the way round, snug but not pressing into the skin.
- Measure twice. If the two readings differ by more than a centimeter, measure a third time and take the average.
When the ratio doesn’t apply
The categories are for adults. They aren’t used during pregnancy, and NICE applies them to people with a BMI under 35. If your result worries you, a doctor can look at it together with your blood pressure, blood sugar and cholesterol.
Using it with your other numbers
Your BMI and your waist-to-height ratio answer different questions, and the two together give a fuller picture. If you’d like to bring your waist down, a modest calorie deficit and regular activity are the proven route: the calorie deficit calculator sets a safe pace. In Calorix, Toasty cheers on the habits, never your measurements.
