FitDexWaist-to-hip ratio calculator
BMI tells you how much you weigh. Not where that weight sits. Fat around the abdomen counts as a signal in its own right, independent of total weight, so the same BMI of 27 can describe two quite different bodies, and the cheapest instrument for telling them apart is a tape measure from the drawer. Enter your waist, hip and height below and we'll work out all three measures and your target waist.
Target waist
Half your height · 9 cm to go
- Fat distributionApple shapePear shapeBalanced
- Above the WHO thresholdTo the WHO threshold4 cm
Apple shape — fat sits mainly around the abdomenPear shape — fat sits mainly on hips and thighsBalanced distribution — waist and hip are close to each other
Waist size means something as a trend, not as a single reading: measuring once a month under the same conditions says far more than a one-off number. FitDex keeps your measurements alongside your weight and calorie history.
How to measure waist and hips
Every threshold on this page was established for one specific measurement method; put the tape somewhere else and the number stops being comparable with them. Because a two-centimetre shift can move someone from one risk band to the next, the method matters more here than the arithmetic.
- Waist: the midpoint between the lowest rib and the top edge of the hip bone. Not the navel — its position varies from person to person, and it is not the measurement the thresholds are based on.
- Measure at the end of a normal breath out; don't pull your stomach in and don't hold your breath. Both shrink the number by a few centimetres.
- The tape should be parallel to the floor, touching the skin but not compressing it. Don't measure over thick clothing.
- Hips: measure at their widest point, with your feet together and your weight evenly on both feet.
- Measure at the same time of day every time so the readings stay comparable — first thing in the morning, before eating, is the most consistent. The figure can move by a few centimetres during the day.
How is it calculated?
The waist-to-hip ratio is waist circumference divided by hip circumference. In the sample body, 98 ÷ 104 = 0.94. The World Health Organization's threshold is 0.90 for men and 0.85 for women; above it counts as abdominal obesity. The thresholds differ by sex because women's hip circumference is naturally larger, which enlarges the denominator and pushes the same waist measurement to a lower ratio than it would give in a man; one shared threshold would systematically under-flag abdominal fat in women.
Waist circumference is also a measure in its own right, with two levels: for men, 94 cm is increased risk and 102 cm substantially increased; for women the same thresholds are 80 and 88 cm. These numbers are not the same information the ratio gives — in a body where waist and hip grow together the ratio can stay flat while the absolute measure crosses the threshold.
The third measure is waist-to-height: waist ÷ height. The boundary is 0.5 for both sexes — keep your waist to less than half your height — and because this one is not split by sex it travels between populations more comfortably than the other two do. Above 0.6 counts as high risk. In the sample body, 98 ÷ 178 = 0.55. Above the healthy line, below the high-risk one.
The target waist comes from this third measure, because it is the one that gives a concrete goal: height × 0.5. In the sample, 178 × 0.5 = 89 cm, and the gap to the current measurement is 9 cm. The other two measures say "stay under the threshold"; this one says "get down to this number".
The worst of the three measures sets the overall result. Averaging would be wrong, because two measures coming out fine does not cancel the signal the third one is giving, and the arithmetic mean of the three would produce a number with no counterpart in any study. In the sample body, waist-to-hip is high and the other two increased. So the overall result is high.
The measurement method matters more than the arithmetic, because a two-centimetre shift can move someone from one risk band to the next. The waist is measured at the midpoint between the lowest rib and the top of the hip bone, at the end of a normal breath out; the hip at its widest point. Detailed instructions are at the bottom of the page.
How to read your result
The sample body shows exactly why all three measures are needed. Waist-to-hip is 0.94, above the threshold; waist circumference is 98 cm, in the increased band but under the second threshold of 102; waist-to-height is 0.55, above the healthy line and below the high-risk one. A page looking only at waist size would say "moderate"; one looking only at the ratio would say "high". Both are incomplete answers.
Which measure comes out worst varies from person to person, and that in itself is information. If waist and hip have grown together, the ratio stays normal while waist-to-height rises; if the fat has gathered mainly around the belly, the ratio stands out. Watching which one improves first as you lose weight shows where the change is coming from.
The target waist is not a weight target. Waist size can fall at an unchanged weight, and it can stay put while weight drops. That is why tracking the scale and the tape together says more than either alone — particularly for someone training, because there the scale compresses two different changes into one number.
The apple and pear distinction is a shorthand for distribution, not a label. Fat gathering around the abdomen and fat gathering on hips and thighs do not give the same metabolic picture; abdominal fat is treated as a signal in its own right. This distribution is largely genetic, so "choosing to be a pear" is not possible — but reducing waist size is.
A measurement landing just under or just over a threshold does not mean two different situations. The difference between 0.89 and 0.91 can appear from a one-centimetre shift in measurement, which is why the tool calls the narrow band around the threshold "balanced". A result close to the line should be read as a warning marker, not a firm classification.
One measurement is a starting point. The trend is the real information. Measuring once a month with the same method at the same time of day says far more than a single reading, because waist size moves by a few centimetres over the course of a day with food and bloating, so two readings taken at different hours have quietly measured two different things.
Frequently asked questions
What should my waist-to-hip ratio be?
The World Health Organization targets below 0.90 for men and below 0.85 for women; above that is classified as abdominal obesity. The thresholds differ by sex because women's hip circumference is naturally larger. But this ratio alone is not enough: when waist and hip grow together the ratio can stay flat, which is why the tool also computes waist circumference and waist-to-height.
My BMI is normal but my waist is over the threshold. Which should I trust?
They answer different questions, and neither cancels the other. BMI measures weight relative to height; it doesn't know where that weight sits. Waist circumference measures the accumulation around the abdomen directly, and that accumulation is treated as a signal in its own right, independent of total weight. A normal BMI alongside an over-threshold waist is a combination that does occur, and in that case the waist is the measure to act on. Use both pages together: BMI gives the total, this tool gives the distribution.
How quickly does waist size come down?
We don't put a number of days here, because it varies from person to person and inventing one would be exactly that — invented. What can be said is that waist size does not move at the same pace as weight. There are stretches where the scale is flat while the tape shrinks, and stretches where the reverse happens. That is why measuring monthly rather than weekly, and following both figures together, makes more sense: at weekly intervals the real change is buried under day-to-day fluctuation.
Can't I just measure around my navel?
You can, but the number won't be comparable with the thresholds on this page. Those thresholds were set from measurements at a specific point — the midpoint between the lowest rib and the top of the hip bone. The navel's position varies between people and shifts with weight, so it gives a consistent reference neither across people nor across one person's measurements over time. For tracking your own change, measuring at the navel still works, as long as you use the same point every time and don't compare it against the thresholds.
Related tools
- BMI calculatorEnter your height and weight to see your body mass index, which category it falls in and the healthy weight range for your height. A body fat estimate comes with it — it says what BMI alone cannot.
- Body fat calculatorEstimate your body fat percentage and lean mass from height, weight, age and sex. We don't ask for a tape measure — and we explain why, along with the margin of error.
- Ideal weight calculatorWork out the healthy weight range for your height. We don't hand you a single "ideal weight" number — because there isn't one. You get the range, where you sit in it, and which end fits you.
- Weight loss timelineSee how many weeks it takes to reach your goal weight — under both a fixed calorie intake and one you re-adjust each week. The two dates aren't the same, and we explain why.
This tool is for information only and is not a substitute for medical diagnosis or treatment. Talk to a healthcare professional before making a lasting change to how you eat.