Waist-to-hip ratio is your waist measurement divided by your hip measurement. For body shape, it describes how defined your waist is: around 0.7 is clearly defined, around 0.8 gently defined, and 0.9 or more means the waist is close to the hips. On its own it cannot name a shape; paired with a second ratio, bust to hips, it places you among the five. The same number is also used in health screening, where it is measured differently and answers a different question; our calculator does not assess it.
The Body Shape Calculator shows both ratios as soon as you enter bust, waist and hips.
How to calculate it
Measure your natural waist, the narrowest part of your torso, at the end of a normal breath out. Measure your hips around the fullest part of the seat. Divide the first by the second, in the same unit; the result has no unit. A 30-inch waist over 40-inch hips gives 0.75; 76 cm over 98 cm gives 0.78. The measuring guide covers the protocol and the usual mistakes.
What 0.7, 0.8 and 0.9 mean for shape
Each of the five shapes has a reference value for waist ÷ hips, the point where it is most typical, and a spread around it:
| Waist ÷ hips | What it describes | Shapes with a reference value nearby |
|---|---|---|
| About 0.70 | Clearly defined waist | Hourglass 0.70, pear 0.74 |
| About 0.80 | Gently defined waist | Inverted triangle 0.80, rectangle 0.82 |
| About 0.90 to 0.95 | Waist close to the hips | Apple 0.95 |
The table shows why the waist ratio alone is not enough. Hourglass and pear share almost the same waist; so do rectangle and inverted triangle. What separates them is the second ratio.
Waist-to-hip ratio says how defined your waist is. Bust-to-hip ratio says what it is defined between.
The second ratio: bust to hips
Bust divided by hips tells you whether your top and bottom halves are balanced. Put the two ratios together and the five shapes fall into a simple grid. Each cell shows where the calculator’s top result lands:
| Bust ÷ hips about 0.88 | About 1.00 | About 1.12 | |
|---|---|---|---|
| Waist ÷ hips about 0.70 | Pear | Hourglass | Inverted triangle |
| About 0.82 | Pear | Rectangle | Inverted triangle |
| About 0.95 | Apple | Apple | Apple |
Read across the top row and you see why “0.7” does not mean hourglass by itself: with a small bust it reads pear, with a large one inverted triangle. Read down the bottom row and you see why the apple is the only shape decided by the waist alone.
How our calculator decides
There are no hard cut-offs. For each shape, the calculator compares your two ratios with that shape’s reference values:
| Shape | Bust ÷ hips | Waist ÷ hips |
|---|---|---|
| Hourglass | 1.00 (spread 0.05) | 0.70 (spread 0.07) |
| Pear | 0.88 (spread 0.07) | 0.74 (spread 0.08) |
| Rectangle | 1.00 (spread 0.05) | 0.82 (spread 0.06) |
| Inverted triangle | 1.12 (spread 0.07) | 0.80 (spread 0.10) |
| Apple | 1.02 (spread 0.10) | 0.95 (spread 0.08) |
Each ratio earns a closeness score that falls off smoothly, like a bell curve: full marks at the reference value, about 60 percent of full marks one spread away, under 15 percent two spreads away. The two ratio scores are averaged. Then your shoulder answer adjusts two shapes: shoulders wider than your hips multiply the inverted triangle score by 1.2 and the pear score by 0.8; narrower shoulders do the reverse.
The shapes are ranked by score, and the result page shows all five. When the top two are within ten points, it adds a note that you are close to the second shape too. A worked example: bust 36, waist 30, hips 37 inches gives 0.97 and 0.81, which scores 93% rectangle; the next three shapes all sit between 54% and 57%.
The spreads differ on purpose. The inverted triangle’s wide waist spread means its waist can be straight or defined; the apple’s wide bust spread means its bust can be any size. The rectangle’s narrow spreads mean it needs balance on both counts.
The health meaning is a different measurement
Health screening uses waist-to-hip ratio as a marker of where the body stores fat. A WHO expert consultation in 2008 reviewed it alongside waist circumference and reported cut-offs for substantially increased risk of metabolic complications: a ratio of 0.85 for women and 0.90 for men. It also considered how the relationship varies with sex, age and ethnicity.
Two things make that a separate question from body shape. The measuring point differs: the WHO protocol places the waist tape midway between the lowest rib and the top of the hip bone, which is not always the narrowest point that styling uses. And the purpose differs: a screening threshold is read by a clinician alongside other information, not used to choose a dress. Our calculator measures for fit only. If you want to know what your ratio means for your health, ask a doctor and measure their way.
What not to read into it
You will see 0.7 described online as an “ideal”. On this site, 0.70 is simply the center of the hourglass reference: a description of one proportion among five, none better than another. Shape changes with age and weight are covered in body shape after 40, and the five shapes side by side in what body shape am I.