Waist ratio calculator
Waist-to-hip and waist-to-height ratios together — what BMI cannot see about where the weight sits.
BMI says nothing about where weight is carried, and the difference turned out to matter, which is why waist measurements are now taken alongside it. WHO set out waist-to-hip thresholds in a 2008 expert consultation; waist-to-height has become more common lately because it compresses to one sentence — keep your waist under half your height. This screen shows the numbers and the reference lines, and makes no judgement.
Measurements
What you enter is saved in this browser, so it is still here next time
WHR reference 0.90
Midpoint between the lowest rib and the top of the hip bone.
Two ratios
Waist ÷ height
0.49
Waist ÷ hip
0.89
Half your height
87.5 cm
The waist at which waist-to-height equals 0.5.
The 0.5 reference does not mean disease above it; it is where risk was observed to rise.
The WHO reference for waist-to-hip is 0.9.
This shows numbers and reference lines and makes no judgement. A series measured the same way is worth more than a single reading.
A statistical reference, not a medical diagnosis. Interpretation belongs with a doctor and test results.
Two divisions, plus half your height
Waist-to-height is the waist divided by height; waist-to-hip is the waist divided by hip. A waist of 85 cm, hip of 95 cm and height of 175 cm gives 0.49 and 0.89. Both are shown to two decimal places and carry no unit. “Half your height” is the waist at which waist-to-height equals 0.5, so 87.5 cm for 175 cm — a number you can hold a tape against, which is why it gets its own card.
Two reference lines, and sex changes only one of them
The 0.5 reference for waist-to-height is the same regardless of sex or age. For waist-to-hip, WHO's 2008 report lists 0.90 for men and 0.85 for women, so choosing a sex switches that value. Both are statistical positions above which metabolic disease was observed more often, not a verdict on an individual. The screen does not change colour or attach a grade when a value crosses a line.
0.01 is one to two centimetres of waist
At 170 cm tall, 1.7 cm of waist is 0.01 of waist-to-height. Where the tape sits and how hard it is pulled easily moves 2 cm, so differences in the second decimal are within measurement error. Rather than reading a 0.01 change from one day to the next, measure in the same place at the same time of day and watch months. Your inputs stay in this browser.
What this screen does not do
It does not compare the waist circumference itself against a threshold. The 90 cm for men and 85 cm for women commonly used in Korea are circumference thresholds; only the two ratios live here. There are no age- or ethnicity-specific lines, and body fat and BMI are on their own screens. If either circumference is zero, that ratio is left blank.
Common questions
QWhere is the waist measured?
The WHO protocol uses the midpoint between the lowest rib and the top of the hip bone. Measuring at navel height is also common and gives a slightly different number, so pick one and always use the same place. Measure after breathing out, tape level with the floor, snug without compressing.
QWhat if the number is past the reference line?
This screen does not answer that. A reference line does not mean disease above it; it means risk was observed to rise above it, and what that means for one person is for a doctor with test results in hand. What is useful here is a series measured the same way, not one reading.
QWhich should I look at, waist-to-height or waist-to-hip?
They look at different things. Waist-to-height is the size of the abdomen relative to the body, so people of different heights can be compared; waist-to-hip is about whether weight sits at the waist or the hips. When the hips grow along with the waist, waist-to-hip stays put while waist-to-height rises, which is why the screen shows both side by side.
QDoes being short put me at a disadvantage on waist-to-height?
No — that is the reason the ratio exists. An 80 cm waist is 0.50 at 160 cm tall and 0.44 at 180 cm, so the same circumference reads differently with body size. Dividing by height is less affected by build than a single circumference threshold applied to everyone.