Waist-to-Height Ratio Calculator
Is your waist less than half your height?
Midway between the lowest rib and the top of the hip bone, after breathing out normally — NICE's instruction.
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An estimate from a formula, not a measurement. It does not replace a doctor, a dietitian or a qualified trainer — least of all with a health condition, during pregnancy or breastfeeding, or under 18.
How this was worked out
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Guide: A tape-measure rule2 min read
A tape-measure rule
The waist-to-height ratio is your waist divided by your height, in the same unit. The rule to remember is simple: keep your waist to less than half your height. Since 2025, NICE recommends measuring it alongside BMI for anyone with a BMI below 35, with three ranges: 0.4 to 0.49 healthy; 0.5 to 0.59 increased health risk; 0.6 or more high health risk.
Why it matters
BMI cannot see where the weight sits. Weight carried around the middle tracks with type 2 diabetes and heart disease more closely than total weight, and two people with the same BMI can sit far apart on this measure. Unlike BMI, the same ranges hold for men and women and across ethnic groups. It is a screening measure, not a diagnosis.
How to measure
Midway between the lowest rib and the top of the hip bone, standing, after breathing out normally, the tape level and snug without pressing. Measure twice and use the average. Nothing you type is kept.
How we calculate
Waist-to-height ratio (2025)
waist ÷ height, in the same unit
Source: National Institute for Health and Care Excellence. Overweight and obesity management (NG246). 2025. Waist-to-height ratio: 0.4 to 0.49 healthy central adiposity, 0.5 to 0.59 increased health risks, 0.6 or more high health risks.
Frequently asked questions
What is a healthy waist-to-height ratio?
Under 0.5, which means a waist less than half your height. NICE (2025) puts 0.4 to 0.49 as the healthy range, 0.5 to 0.59 as increased health risk and 0.6 or more as high health risk. The same ranges hold for men and women and across ethnic groups.
How do I measure my waist?
NICE's instruction: midway between the lowest rib and the top of the hip bone, after breathing out normally, the tape level and snug but not pressing. Measure twice and use the average.
Is it better than BMI?
It sees what BMI cannot: where the weight is carried. Weight around the middle tracks with type 2 diabetes and heart disease more closely than weight alone, which is why NICE now recommends measuring it alongside BMI.
What if my ratio is below 0.4?
The ratio alone says little there. It can be a reason to look at your weight and diet with a health professional.
Does it work in inches?
Yes. Waist and height just need the same unit; the ratio is the same either way.