What it means
Waist-to-height ratio is a measurement, not an estimate — one division, waist over height. It flags central fat, the kind that sits around organs, which scale weight and BMI both miss. The rule is simple: keep your waist under half your height.
Zones
| Ratio | Zone |
|---|---|
| below 0.40 | Slim |
| 0.40–0.49 | Healthy |
| 0.50–0.59 | Increased risk |
| 0.60 and above | High risk |
Ashwell / WHO-NICE screening bands. A screening flag, not a diagnosis.
Ideal waist for your height
| Height | Reference | Watch | Higher risk |
|---|---|---|---|
| 150 cm | under 75 | 75–90 | over 90 |
| 155 cm | under 77.5 | 77.5–93 | over 93 |
| 160 cm | under 80 | 80–96 | over 96 |
| 165 cm | under 82.5 | 82.5–99 | over 99 |
| 170 cm | under 85 | 85–102 | over 102 |
| 175 cm | under 87.5 | 87.5–105 | over 105 |
| 180 cm | under 90 | 90–108 | over 108 |
| 185 cm | under 92.5 | 92.5–111 | over 111 |
| 190 cm | under 95 | 95–114 | over 114 |
| 195 cm | under 97.5 | 97.5–117 | over 117 |
| 200 cm | under 100 | 100–120 | over 120 |
| 4'10" | under 29" | 29–34.8" | over 34.8" |
| 4'11" | under 29.5" | 29.5–35.4" | over 35.4" |
| 5'0" | under 30" | 30–36" | over 36" |
| 5'1" | under 30.5" | 30.5–36.6" | over 36.6" |
| 5'2" | under 31" | 31–37.2" | over 37.2" |
| 5'3" | under 31.5" | 31.5–37.8" | over 37.8" |
| 5'4" | under 32" | 32–38.4" | over 38.4" |
| 5'5" | under 32.5" | 32.5–39" | over 39" |
| 5'6" | under 33" | 33–39.6" | over 39.6" |
| 5'7" | under 33.5" | 33.5–40.2" | over 40.2" |
| 5'8" | under 34" | 34–40.8" | over 40.8" |
| 5'9" | under 34.5" | 34.5–41.4" | over 41.4" |
| 5'10" | under 35" | 35–42" | over 42" |
| 5'11" | under 35.5" | 35.5–42.6" | over 42.6" |
| 6'0" | under 36" | 36–43.2" | over 43.2" |
| 6'1" | under 36.5" | 36.5–43.8" | over 43.8" |
| 6'2" | under 37" | 37–44.4" | over 44.4" |
| 6'3" | under 37.5" | 37.5–45" | over 45" |
| 6'4" | under 38" | 38–45.6" | over 45.6" |
| 6'5" | under 38.5" | 38.5–46.2" | over 46.2" |
| 6'6" | under 39" | 39–46.8" | over 46.8" |
Waist in cm (metric rows) or inches (imperial rows), at the same units as your height. These 0.5 and 0.6 cut-points are general adult guidelines — children use a different scale, and above about 190 cm the half-height rule is less precise.
Waist-to-hip ratio (a second view)
If you also enter your hips, the calculator adds your waist-to-hip ratio — another measured indicator with sex-specific risk bands (WHO). Waist-to-height needs only two measurements and works across heights; waist-to-hip adds information about fat distribution. Both are screening measures, not diagnoses.
FAQ
What is the ideal waist size to height ratio?
Below 0.5 — waist less than half your height. The rule is easy to remember and, unlike BMI, it reflects where fat sits. Central fat is more closely linked to metabolic risk than total weight.
What is the ideal waist size for 5'7" height?
Half your height is the common guideline — about 33.5 inches (85 cm) for 5'7". The ratio matters more than the number: below 0.5 is the general reference, and it applies across heights and both sexes.
Is waist-to-height better than BMI?
For screening central fat it often is: it captures where fat sits, which BMI ignores. It needs only a tape measure and your height.
How do I measure my waist correctly?
At the narrowest point between ribs and hips, or at the navel — pick one and keep it. Exhale normally, tape snug, not tight.
Does it work during pregnancy?
No. Waist-based ratios are not valid during pregnancy and should not be used to screen then.