Waist-to-Height Ratio Calculator
Calculate your waist-to-height ratio and see your NICE NG246 central adiposity category, plus the waist size that puts you at a 0.5 ratio.
Last reviewed
Waist-to-height ratio (WHtR) flags abdominal fat risk by comparing waist circumference to height, calculated as WHtR = waist ÷ height. NICE's 2022 guideline (NG246) classifies adults into four bands from this single number, and its simplest rule of thumb is: keep your waist under half your height.
Waist-to-Height Ratio
0.47
Target Waist (for 0.5)
34in
To Reach 0.5
Already there
Measurements
Pair This With
BMI catches total weight relative to height; WHtR catches where that weight sits. Neither replaces the other. NICE recommends using them together.
Central Adiposity Status
NICE NG246 Classification Gauge
Healthy
NICE classifies 0.4-0.49 as healthy central adiposity, indicating no increased health risk from abdominal fat.
Why NICE Added This Alongside BMI
BMI compares total weight to height and cannot tell where fat is carried. Waist-to-height ratio isolates abdominal ("central") fat, which sits closer to the liver and major organs and carries more cardiometabolic risk (type 2 diabetes, hypertension, cardiovascular disease) than fat stored elsewhere on the body. Two people with an identical BMI can have very different WHtR values, and the one carrying more weight around the middle is the one NICE's guidance is designed to flag.
NICE NG246 (the 2022 update to the earlier CG189 guidance) classifies adults with a BMI under 35 into four waist-to-height bands, and states its headline message plainly: try to keep your waist circumference to less than half your height.
The WHtR Formula
A Worked Example
This calculator's defaults (a 32in waist and a 68in height) give WHtR = 32 ÷ 68 ≈ 0.47, which NICE classifies as healthy central adiposity (no increased health risk from abdominal fat). Half of 68in is 34in, so this person has 2 inches of margin before crossing into the increased-risk band at 0.5.
Someone the same 68in tall with a 38in waist would have WHtR = 38 ÷ 68 ≈ 0.56, inside the 0.5-0.59 increased-risk band, and 4 inches above the 34in target for a 0.5 ratio.
WHtR vs. BMI, Briefly
Neither measure replaces the other. BMI is a fast, well-studied screen for total body weight relative to height, but it can misclassify very muscular people as overweight and can miss abdominal fat in people at a "normal" weight. WHtR is simpler to measure incorrectly (waist placement varies) but captures fat distribution that BMI structurally cannot. NICE's current guidance is to use both together for adults with a BMI under 35, not to pick one over the other.
What This Doesn't Cover
NICE's WHtR bands apply to adults with a BMI under 35; above that, other NICE obesity guidance takes over and this ratio is less useful as a standalone signal. This calculator is not intended for use during pregnancy, when waist circumference no longer reflects the same thing, and it is not intended for children or young people, who are assessed against separate age- and sex-specific growth-based guidance rather than the fixed adult bands used here. Measurement technique also matters: NICE advises measuring the waist standing, midway between the bottom of the lowest rib and the top of the hip bone, at the end of a normal exhale, without pulling the tape tight enough to compress skin.
Waist-to-Height Ratio Inquiries
?Is waist-to-height ratio better than BMI?
They measure different things. BMI compares weight to height and can't tell where fat sits on the body; waist-to-height ratio (WHtR) focuses on abdominal fat, which is more strongly linked to cardiometabolic risk than total body fat. NICE NG246 now recommends using both together for adults with a BMI under 35. WHtR adds information BMI alone misses, rather than replacing it.
?Why does NICE only classify ratios of 0.4 and above?
NICE NG246's classification table for central adiposity begins at a waist-to-height ratio of 0.4 and works upward through three bands to 0.6+. It does not publish a specific risk label for ratios below 0.4. The guidance is built to flag increasing abdominal fat risk, not to classify very low ratios.
?Does this apply to everyone?
NICE's WHtR classification applies to adults with a BMI under 35, of either sex and any ethnicity, including adults with high muscle mass. It is not intended for use during pregnancy, and children and young people are assessed against separate age- and sex-specific NICE guidance, not the adult bands used here.
?What does 'keep your waist to less than half your height' mean in practice?
It's NICE's plain-language version of keeping WHtR under 0.5 (the boundary between the 'healthy' and 'increased risk' bands). For someone 68 inches tall, that means keeping waist circumference under 34 inches.
?My BMI is healthy but my WHtR is in the increased-risk band. Which one matters more?
This is exactly the situation WHtR is designed to catch. Someone can have a healthy BMI while carrying disproportionate abdominal fat, which BMI alone won't reveal. NICE's guidance treats an elevated WHtR as a meaningful signal on its own, worth discussing with a clinician, even alongside a normal BMI.
About this calculator. Results are estimates for education and planning, based on the inputs you enter and the published formula described above. Everything runs in your browser; nothing you type is sent to us or stored. It is not financial, tax, legal or medical advice. Read the disclaimer and our methodology.
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