Waist-to-Height Ratio Calculator
Keep your waist under half your height.
Calculate your waist-to-height ratio, a simple screening measure that predicts metabolic risk better than BMI and needs only a tape measure.
Measured at the navel, breathing out normally.
Waist-to-height ratio
0.49
Slim / low risk
Under 0.5, your waist is less than half your height, which is the target.
Waist-to-height ratio categories
| Category | Ratio |
|---|---|
| Slim / low riskYou | Below 0.5 |
| Increased risk | 0.5 – 0.6 |
| High risk | 0.6 and above |
How the Waist-to-Height Ratio Calculator works
This is the rare health metric that fits in one sentence: keep your waist under half your height. It needs no chart, works across adults of most heights and ethnicities, and in several studies has outperformed BMI at flagging cardiometabolic risk.
Also known as: WHtR calculator · waist height ratio health · waist to height risk · waist to height ratio · height to waist ratio · waist to height calculator · width to height ratio calculator · waist and height
The simplest useful screening number
Waist-to-height ratio is waist circumference divided by height, in the same units. The guidance that follows from it is unusually memorable: keep your waist to less than half your height.
That single rule performs comparably to more complex measures for predicting cardiometabolic risk, and it needs one measurement plus a height most people already know.
It has a further practical advantage: the same threshold applies across adults of both sexes and, with some adjustment, across children from around age six. Very few health metrics manage that.
The evidence behind it
Several large meta-analyses have found waist-to-height ratio to be at least as good as BMI, and generally better, at predicting cardiovascular disease, type 2 diabetes and all-cause mortality.
The UK's National Institute for Health and Care Excellence now recommends it as a screening measure alongside BMI for adults with a BMI under 35, specifically to capture central adiposity that BMI misses.
The mechanism is straightforward: the measure captures abdominal fat, which is the deposit most strongly associated with metabolic dysfunction, and it scales that against body size so that the same waist means something different on different frames.
The categories
Below 0.4 is generally considered underweight for the measure and may warrant attention in the other direction. From 0.4 to 0.49 is the healthy range. From 0.5 to 0.59 indicates increased risk. At 0.6 and above, risk is substantially elevated.
The 0.5 boundary is the one that matters and it is where the memorable rule comes from. Someone 175 centimetres tall should aim to keep their waist under 87.5 centimetres.
For children, an adjusted approach is used with a threshold nearer 0.5 as well, though paediatric assessment properly involves growth charts and a clinician rather than a single ratio.
Measuring the waist properly
The measurement point should be consistent, and the two common conventions are the midpoint between the lowest rib and the iliac crest, or the narrowest point of the torso. Either works for tracking; mixing them does not.
Measure directly against skin or over light clothing, standing, at the end of a normal exhalation, with the tape horizontal all the way round. Do not hold the stomach in, which is the most common source of error and which people do without noticing.
Taking the measurement at the same time of day helps, since abdominal circumference varies through the day with food and fluid. First thing in the morning before eating is the most reproducible point.
What to do with the result
A ratio in the healthy range is reassuring on this specific dimension and does not exclude other risks. Blood pressure, lipids, glucose, family history and smoking all matter independently.
A ratio above 0.5 is a reason to look at the modifiable contributors rather than a diagnosis. Abdominal fat responds to the same things as fat generally: energy balance, activity, sleep and alcohol. Nothing targets it specifically, despite what a great deal of marketing claims.
A ratio above 0.6, or a ratio rising steadily, is worth raising with a doctor, because it is a marker that reasonably prompts checking the things it is associated with rather than something to address alone.
Where to go next
The Waist-to-Height Ratio question rarely arrives on its own. These are the ones that usually come with it:
- Waist-to-Hip Ratio Calculator — Where you carry fat, and what the WHO says about it.
- BMI Calculator — Body mass index with category and healthy weight range.
- Body Fat Calculator — Body fat percentage from tape measurements.
- Calorie & BMR Calculator — Daily calorie needs for losing, holding, or gaining weight.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
How is waist-to-height ratio calculated?
Divide your waist circumference by your height in the same units. A 32-inch waist on a 70-inch frame is 32 ÷ 70 = 0.46. Because it is a ratio, inches and centimetres give the same answer as long as you do not mix them.
What is a healthy waist-to-height ratio?
Below 0.5 is the target for adults. 0.5 to 0.59 indicates increased risk, and 0.6 or above indicates high risk. UK NICE guidance recommends this measure alongside BMI precisely because the 0.5 threshold is so easy to remember and apply.
Why is this better than BMI?
BMI cannot tell where weight sits, and abdominal fat is the part most strongly linked to metabolic disease. Waist-to-height captures that directly, and unlike waist circumference alone it does not need different thresholds for different heights.
Does it work for children?
The 0.5 boundary has been studied in children over about age 6 and performs reasonably, but paediatric assessment normally uses age- and sex-specific BMI percentile charts. Use this as a rough check, not a diagnosis, and raise concerns with a paediatrician.
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