Waist to Height Ratio Calculator

How to use this waist to height ratio calculator

Two numbers are enough to get a result. The optional ones each unlock something specific rather than just decorating the page.

1. Say where you put the tape. This is not a formality. The cut-offs this tool uses were set with the tape midway between the lowest rib and the top of the hip. American clinical practice measures at the top of the hip bone instead, and on the same person that usually reads a little larger. Picking the wrong one can move you across a boundary.
2. Enter your waist and height. They can use different units, since plenty of people own an inch tape and know their height in centimetres. Measure over bare skin, breathe out naturally first, and don’t pull the tape tight enough to dent anything.
3. Read the target waist, not just the ratio. The middle panel converts the guidance into a measurement: keep your waist under this many inches. That is the number worth remembering, because you can check it with a tape and no arithmetic.
4. Add your weight if you want the honest version. It computes your BMI, tells you whether the two measures agree, and flags the case where this ratio stops being the measure the guideline uses at all.
5. Save or share it. The PDF fits one page with your inputs, your band and the sources, which makes it something you can hand to a clinician. The share link reopens with your values in it.

Why this tool is different from other waist to height ratio calculators

Dividing one number by another is not hard, and every page ranking for this term does it correctly. What almost none of them do is tell you what to do with the answer. Here is what is different:

• It answers the question people actually type. Google’s own related questions for this term are “what is my ideal waist size for my height” and “what should my waist be at 5 foot 7”. Both are asking for a measurement, not a ratio. This tool prints one, in inches and centimetres, along with how far above or below it you currently are.
• It knows when the ratio stops applying. The guideline behind these bands applies them to adults with a BMI under 35. Above that, BMI has already classified the risk and the ratio adds nothing. Enter a weight that crosses the line and this tool says so. Every other calculator on page one will hand back a confident green or red result regardless.
• It asks where the tape went. Two documented measurement sites are in common use and they give different numbers on the same body. No conversion is invented here, because there is no reliable single one. Instead the tool tells you which site the bands assume and flags a borderline result for re-measurement.
• It names the disagreement instead of hiding it. A healthy BMI alongside a raised waist ratio is a recognised pattern with a real risk attached, and so is the opposite case where muscle inflates BMI. The tool detects both and says which one is happening.
• It gets the ethnicity question the right way round. BMI thresholds are lower for several backgrounds. The waist-to-height bands are not, deliberately, and that asymmetry is the single most useful thing on this page. No other calculator ranking for this term mentions it.
• No login, no newsletter wall, no ads, and it embeds free. Two of the top ten results put a sign-up or a terms-acceptance step between you and a division.

How it works (the math)

The formula is one division, with both measurements in the same unit:

WHtR = waist ÷ height

A 38-inch waist on a 67-inch frame gives 0.57. So does a 96.5 cm waist on a 170 cm frame, because the ratio has no units. Those are NICE’s own two worked examples, and both are asserted as test fixtures that run on every build of this site.

The bands come from NICE guideline NG246, recommendation 1.9.14:

• 0.40 to 0.49 — healthy central adiposity, no increased health risks
• 0.50 to 0.59 — increased central adiposity, increased health risks
• 0.60 or more — high central adiposity, further increased health risks

Below 0.40 is not a fourth, better band. It sits outside the classified range entirely, and Margaret Ashwell, whose 2011 shape chart these boundaries come from, marks that zone “take care, you might be underweight”. There is no prize for driving this number down.

Three things about those bands are worth knowing, because they are exactly the parts other calculators drop. They apply from age 5 upward, unchanged, which is unusual for a body measurement. They apply to both sexes and all ethnicities, also unchanged, which is why several calculators showing sex-specific waist-to-height tables are working from an older and more granular research convention rather than the current guideline. And they apply to adults with a BMI below 35, which is the limit almost nobody surfaces.

That BMI ceiling deserves a sentence of its own. The reason waist-to-height ratio was adopted at all is that BMI cannot see where fat sits, so two people at the same BMI can carry very different risk. Past a BMI of 35 that ambiguity is gone. The extra measurement has nothing left to add, and a guideline that kept asking for it would be asking for busywork.

The measurement itself is the weak link, not the arithmetic. Waist circumference is among the least repeatable measurements in routine practice. Tape height, tape tension, and whether you breathed out all move it, and the research finds that training clinicians in it barely helps. That is why this tool flags any result within 0.02 of a boundary rather than pretending the second decimal place is solid.

Worked examples

A 5 foot 10 adult with a 34-inch waist

34 divided by 70 is 0.49, the top of the healthy band with about half an inch of room before the half-your-height line at 35 inches. Nothing to act on. The useful part is that 35-inch figure: it is a number you can check with a tape once a year without doing any arithmetic, and this measurement tends to drift upward slowly rather than jump.

A 5 foot 7 adult, 32-inch waist, 165 lb

The ratio is 0.48, comfortably healthy, and the target waist is 33.5 inches. BMI works out at about 25.8, which lands in the overweight band. This is the disagreement case, and the ratio is the more informative of the two here: BMI counts muscle as weight and has no idea where anything sits. If you lift, or you simply carry more frame than average, this is the pattern you will see. The guideline says as much, which is why it tells clinicians to read BMI with caution in people with high muscle mass while leaving the waist bands untouched for them.

A 5 foot 5 adult, 36-inch waist, 150 lb

BMI comes out around 25, right at the edge of healthy. The ratio is 0.55, squarely in the increased band, and the target waist is 32.5 inches. This is the inverse case and the one worth taking seriously, because the raised risk is invisible to the measure most people check. It has a name in the literature, and the sensible response is not a diet but a conversation about the three specific things a raised ratio predicts. Two of them you can check at home with a home blood pressure monitor and a glucose meter before you ever see anyone.

Frequently asked questions

What is a good waist to height ratio?

Between 0.40 and 0.49. The one-line version, which is how the NHS is told to phrase it, is to keep your waist to less than half your height. Above 0.50 is described as increased central adiposity and above 0.60 as high. Below 0.40 is not better than good, it is outside the range the guideline classifies at all.

What should my waist be at 5 foot 7?

Under 33.5 inches, or about 85 cm, since 5 foot 7 is 67 inches and half of that is 33.5. The high-risk mark for that height sits at 40.2 inches. The same arithmetic works for any height, and the calculator above does it for yours in whichever unit you are holding. This one number is more useful day to day than the ratio itself, because you can verify it with a tape and no maths.

Is waist to height ratio better than BMI?

For central fat, yes, and that is the point of it. BMI is height and weight, so it cannot distinguish muscle from fat or tell you where fat is stored, and where it is stored is what drives cardiometabolic risk. The current guidance does not ask you to choose: it asks for both, and treats them as answering different questions. The two are most informative precisely when they disagree, which is why this calculator will show you your BMI alongside the ratio and tell you when they part company. If you want to go further into body composition, the lean body mass calculator is the next measure along.

Does waist to height ratio differ for men and women?

Not in the current UK guidance. NICE states plainly that the 0.4 / 0.5 / 0.6 classification is for both sexes and all ethnicities, and from age 5 upward. You will find calculators showing separate male and female tables, and they are not making it up: they are working from the older Ashwell and Schneider research bands, which are more granular. The absolute waist circumference cut-offs are a different matter and genuinely do differ by sex, at 102 cm for men and 88 cm for women, with lower figures used for Asian populations. This tool will show you that check too if you enter your sex.

Can I use this for a child?

From age 5, yes, with the same bands and the same message about keeping the waist under half the height. Under 5, no, and neither the NHS nor NICE offers a version that does. Two cautions. Check the child’s BMI centile first, since adult BMI categories are meaningless for a growing body and this calculator deliberately withholds a BMI band for anyone under 18. And do it with them rather than to them: the guideline committee has an open research question about the risks of children measuring their own central adiposity, which is a polite way of saying nobody yet knows what this does to a self-conscious eleven-year-old.

Related tools

• Ideal Body Weight Calculator: four published formulas, with the same show-the-disagreement approach.
• Lean Body Mass Calculator: fat-free mass, for when BMI and the tape disagree.
• TDEE Calculator: daily energy expenditure, the number that moves the one on this page.
• Body Surface Area Calculator: seven BSA formulas at once, plus percentage of body affected.
• Browse all free tools by Dr. Taylor →

Dr. Taylor’s recommendations

The calculator picks from these based on your result. All of them, in one place:

• Best Bathroom Scales. The BMI cross-check on this page is only as good as the weight you feed it, and cheap home scales drift enough to move you a whole category.
• Best Blood Pressure Monitors. Hypertension is one of the three conditions a raised ratio predicts, and it is the one with no symptoms until there are.
• Best Glucose Monitors. Type 2 diabetes is the second. A fasting reading at home costs very little and tells you where you stand.
• Best Fiber Supplements. The least punishing lever on waist circumference, because it improves satiety without asking you to eat less food.
• Best Resistance Bands. Holding onto muscle is what keeps this number stable through your forties and fifties.

Sources & methodology

• NICE guideline NG246, Overweight and obesity management (published 14 January 2025, last updated 8 January 2026): recommendations 1.9.5, 1.9.8, 1.9.10, 1.9.11, 1.9.12, 1.9.14 and 1.9.15 for adults; 1.10.5, 1.10.10 and 1.10.11 for children and young people aged 5 and over; Box 1 for the measurement method and the two worked examples.
• NHS, Calculate your waist to height ratio (page reviewed 25 February 2025): the consumer restatement and the exclusion list this tool follows.
• Ashwell M. Charts Based on Body Mass Index and Waist-to-Height Ratio to Assess the Health Risks of Obesity: A Review. The Open Obesity Journal 2011;3:78–84 — the origin of the 0.4 / 0.5 / 0.6 boundaries.
• Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obesity Reviews 2012;13:275–286.
• Anthropometric Measurement, StatPearls (NCBI Bookshelf): the US measurement site, and the finding that waist circumference is prone to error that training does not fix.
• Secondary Causes of Obesity and Comprehensive Diagnostic Evaluation, StatPearls: the absolute waist cut-offs (102 / 88 cm, and 90 / 80 cm for Asian populations) and the metabolically-unhealthy-normal-weight phenotype.

Every band boundary, unit conversion and edge case on this page is checked against a fixture file on each build, including NICE’s own two worked examples. This tool is reviewed annually, and sooner if NG246 is amended again. About Dr. Taylor · Last reviewed September 4, 2026.

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Free for clinics, nursing and medical educators, dietitians, patient-education sites, and anyone teaching central adiposity. Required attribution is built into the snippet. No fee, no account, no rate limit.

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