Your waist-to-height ratio is your waist measurement divided by your height, in the same units. The NHS advises keeping your waist to less than half your height, which is a ratio below 0.5[1]. A ratio of 0.5 or more suggests extra fat around the middle.
In England, NICE's guideline on overweight and obesity management (NG246) also uses waist-to-height ratio to assess central adiposity alongside BMI.
How to measure your waist
Use a soft tape measure. Stand up straight, find the point midway between your lowest rib and the top of your hip bone, and wrap the tape around your bare middle there. Breathe out normally and read the tape without pulling it tight. Measure twice and use the average.
How the calculator works
The calculator divides your waist by your height. A person 170 cm tall with an 80 cm waist has a ratio of 0.47, under half their height. The NHS waist-to-height ratio check is intended for people with a BMI under 35[1].
Why waist size matters
Fat stored around the abdomen, around the organs, is linked more strongly to type 2 diabetes and heart disease than fat on the hips and thighs. Two people with the same BMI can carry their weight very differently, which is why a waist measurement adds useful information to your BMI.
Bringing your ratio down
Small, steady changes work best: more vegetables, fruit, whole grains and pulses; fewer sugary drinks and less alcohol; regular activity, including strength work; and enough sleep. A dietitian can turn these into a plan that fits your culture, budget and routine.
Book a video, phone or in-person session with a professional from our network. Your result can be attached so you do not start from scratch.
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Frequently asked questions
What is a healthy waist-to-height ratio?
The NHS advises keeping your waist to less than half your height, a ratio below 0.5[1].
Is waist-to-height ratio better than BMI?
They measure different things. BMI compares weight with height; the ratio shows how much of that weight sits around your middle. Used together they give a fuller picture.
Does the ratio work for children?
This calculator is for adults. Children should be assessed by a health professional.
Should I measure with clothes on?
Measure against bare skin or thin clothing for the most accurate result.
Does the calculator store my data?
No. The calculation runs in your browser.
Sources and citations
Every figure on this page was read on the publisher's own page. Where a country or body does not publish a figure we say so instead of estimating.
- NHS (UK National Health Service), Overweight and obesity in adults (reviewed 29 Apr 2026)
