Is 0.5 really universal?

It generalizes well across adult heights and both sexes, though some guidelines add caution zones (0.4–0.5 healthy; >0.6 high risk). One simple line remains the public-health compromise.

How does this compare to BMI?

Two people with identical BMI can have ratios of 0.45 and 0.58; very different risk profiles. WHtR adds the distribution information BMI lacks.

Morning or evening measurement?

Either works if consistent; morning before eating avoids meal-related distension and gives the most comparable trend data.

Health

Waist-to-Height Ratio Calculator

What this does

Check your waist-to-height ratio against the WHO 0.5 boundary to assess central adiposity; a stronger cardiometabolic signal than BMI alone.

Enter your details

Runs in your browser

How to use it

Using the waist-to-height ratio calculator

01
Measure your waist correctly
Find the midpoint between your lowest rib and the top of your hip bone; wrap snugly after exhaling normally.
02
Enter waist and height
Same units for both; centimetres by default.
03
Compare against 0.5
Under 0.5 is the healthy message; the assessment row explains your position relative to the boundary.

Good to know

Why belly location matters

Visceral fat wrapping internal organs behaves differently from subcutaneous fat; it drains straight to the liver and drives insulin resistance, dyslipidaemia and inflammation. Waist-based measures proxy this depot; scale weight and BMI cannot tell where fat lives.

"Keep your waist under half your height"

The memorable slogan encodes the entire threshold. Research reviews find WHtR detects cardiometabolic risk at least as well as BMI and waist alone, supporting its adoption as a first-line screening ratio.

If your ratio is above 0.5

Combine aerobic work with resistance training; spot reduction is myth, overall fat loss is not.
Limit alcohol and sugary drinks, both linked to visceral gain.
Discuss results with a clinician, especially alongside blood-pressure or glucose concerns.

How it's calculated

The math behind this calculator

WHtR = waist(cm) ÷ height(cm)
Boundary: WHtR ≥ 0.5 → increased central-adiposity risk (WHO)

Divide waist circumference by height. The World Health Organization flags ratios at or above 0.5; waist exceeding half your height; as indicating increased health risk from abdominal fat, independent of overall body size.

Unlike BMI, the ratio needs no age-, sex- or ethnic-specific tables: one boundary applies broadly across adult heights, which public-health bodies find attractive for screening.

Assumptions & limitations

Waist measured at the midpoint indicated, standing, relaxed.
Applies to adults; children need percentile charts.
Screens for risk distribution; it is not a diagnosis of any condition.

Worked example

An 82 cm waist at 175 cm tall gives a ratio of about 0.47; under the 0.5 boundary, classed as healthy on this measure.

FAQ

Frequently asked questions

Is 0.5 really universal?: It generalizes well across adult heights and both sexes, though some guidelines add caution zones (0.4–0.5 healthy; >0.6 high risk). One simple line remains the public-health compromise.
How does this compare to BMI?: Two people with identical BMI can have ratios of 0.45 and 0.58; very different risk profiles. WHtR adds the distribution information BMI lacks.
Morning or evening measurement?: Either works if consistent; morning before eating avoids meal-related distension and gives the most comparable trend data.

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