How do I calculate it?

Divide waist by height in the same units. 84 cm ÷ 175 cm = 0.48.

Is it the same for men and women?

Yes. The 0.5 boundary is used for adults regardless of sex or ethnicity, which is one of its advantages.

Is WHtR better than BMI?

It captures central fat, which BMI cannot. NICE recommends using it alongside BMI for adults with a BMI under 35.

Can children use this ratio?

Research supports 0.5 as a useful boundary for older children too, but children's health should be assessed by a professional.

Health · Free tool

Waist-to-Height Ratio Calculator

Keep your waist to less than half your height — check your ratio against NICE bands.

Fat stored around the middle — central adiposity — is linked more strongly to type 2 diabetes, heart disease and high blood pressure than fat stored elsewhere. BMI cannot see where fat sits, but a tape measure can. Waist-to-height ratio (WHtR) divides your waist by your height to give a simple number with one memorable rule: keep your waist to less than half your height.

In the UK, NICE recommends using waist-to-height ratio alongside BMI for adults with a BMI under 35, with these bands: 0.4 to 0.49 healthy, 0.5 to 0.59 increased health risk, and 0.6 or more high health risk. A 2012 systematic review and meta-analysis found WHtR was a better screening tool for cardiometabolic risk than waist circumference or BMI alone.

The same 0.5 boundary applies to men and women and across ethnic groups, which is what makes the ratio easy to use. This calculator gives your ratio, its NICE band, and the largest waist that keeps you under 0.5 for your height.

By DailyCalc Editorial Team · Updated 2026-10-03 · 5-min read · 3 sources cited

● Waist-to-height calculator

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Waist-to-height ratio

WHtR = waist ÷ height (same units for both); healthy waist < 0.5 × height

Because both measurements use the same unit, the ratio has no units — you can use centimetres or inches. NICE adult bands: under 0.4 may indicate low weight; 0.4–0.49 healthy; 0.5–0.59 increased risk; 0.6 and above high risk.

waist: Measured midway between the lowest rib and the top of the hip bone, after breathing out normally.
height: Standing height without shoes.

Worked example: waist 84 cm, height 175 cm

A quick check during a routine health review:

WHtR = 84 ÷ 175 = 0.48.
0.48 falls in the 0.4–0.49 band: healthy.
Maximum healthy waist = 0.5 × 175 = 87.5 cm, so there is 3.5 cm of headroom.
For comparison, a 94 cm waist at 170 cm gives 0.553 — increased risk.
And a 105 cm waist at 172 cm gives 0.61 — high risk.

Result: Ratio 0.48 — healthy. Keep the waist under 87.5 cm at 175 cm tall.

How to measure and use it

Measuring correctly is the whole job.

Step 1: Find the spot

Locate the bottom of your lowest rib and the top of your hip bone; the tape goes halfway between them.

Step 2: Measure after breathing out

Stand relaxed, tape level and snug but not tight. Do not hold your stomach in.

Step 3: Enter waist and height in cm

The calculator divides them and shows your band.

Step 4: Recheck every few months

Waist often changes before weight does, especially with exercise.

Why use it

Where WHtR adds to BMI:

Normal BMI, larger waist

Someone with a healthy BMI can still carry risky central fat; the ratio reveals it.

Tracking lifestyle change

A falling waist shows fat loss from the middle even when the scale barely moves.

Simple self-check

A piece of string your height, folded in half, should fit around your waist — the same 0.5 rule.

Family health conversations

One rule applies to adults of any sex and ethnicity, so it is easy to share.

Pro tips

Make the number reliable:

Measure at the same time of day, ideally in the morning before eating.
Take two readings; if they differ by more than 1 cm, take a third and average the closest two.
Use the same tape each time — cloth tapes stretch with age.
Combine with BMI, as NICE suggests, rather than replacing it.

Common mistakes

Errors that skew the ratio:

Measuring at the belt line

Trouser waistbands often sit below the true waist and give a smaller number.

Holding your breath in

Sucking in can take several centimetres off the measurement.

Mixing units

Waist in inches and height in centimetres gives a meaningless ratio; use the same unit for both.

Using it in pregnancy

The ratio does not apply during pregnancy.

Sources & references

The formula, thresholds and guidance on this page were checked against these primary sources. Written and reviewed by DailyCalc Editorial Team; last updated 2026-10-03. Spotted an error? Tell us.

Disclaimer: Screening indicator only — not a diagnosis. If your ratio is 0.5 or above, or you have health concerns, speak to a GP.

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