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Calculation Machine

Waist to Height Ratio Calculator

A better risk screen than BMI: keep your waist under half your height.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Waist to height ratio
0.491
Category
healthy
Healthy waist target
under 87.5 cm
Change needed
none — you are inside the target
Waist in inches
33.9 in

Working

  1. 186 / 175 = 0.491

Quick answer

Waist to height ratio divides waist by height. Below 0.5 is the healthy target for adults, and it predicts cardiometabolic risk better than BMI.

The formula

WHtR = waist / height

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Waist circumference86 cm
  • Height175 cm

Result

  • Waist to height ratio0.491
  • Categoryhealthy
  • Healthy waist targetunder 87.5 cm
  • Change needednone — you are inside the target
  • Waist in inches33.9 in

How to use the Waist to Height Ratio Calculator

  1. 1Measure your waist at the midpoint between the lowest rib and the top of the hip bone, after breathing out.
  2. 2Enter height in the same unit as your waist measurement.
  3. 3Aim to keep the ratio under 0.5 — the simplest version is keep your waist under half your height.

Frequently asked questions

Is WHtR better than BMI?

For cardiometabolic risk, yes. It captures central fat, which BMI cannot distinguish from muscle or hip and leg mass.

Does the 0.5 boundary apply to children?

The same rule of thumb is used from age six upwards, though clinicians use age-specific charts for formal assessment.

About this calculator

The simplest health check with a tape

Waist-to-height ratio is waist circumference divided by height. A widely used rule is to keep your waist to less than half your height — a ratio under 0.5. It works across sexes and ethnic groups better than many other simple measures and flags abdominal fat that BMI can miss.

The UK's NICE guidance uses 0.4–0.49 as healthy, 0.5–0.59 as increased risk and 0.6 or above as high risk.

Example

A person 170 cm tall with an 88 cm waist has a ratio of 88 ÷ 170 = 0.52 — just into the increased-risk band.

Measuring

  • Measure midway between the lowest rib and the top of the hip bone, after a normal breath out.
  • Use the same units for waist and height.

Sources

More questions

Is waist-to-height ratio better than BMI?

Studies suggest it predicts heart and metabolic risk at least as well, and often better.

Does it apply to children?

The 0.5 cut-off is often used for children over five as well.