Rectangle body shape

What the rule says

Four conditions. The absolute difference between bust and hips is under 3.6 inches (9.1 cm). Bust minus waist is between 0 and 9 inches, so the waist is not larger than the bust and not dramatically smaller. Hips minus waist is between 0 and 10 inches, the same idea for the hips. The lower bounds of zero were added in the 2020 revision; without them a waist larger than the bust or hips could be returned as Rectangle.

Rectangle and its four neighbours

Why it is the most common result

Because it is defined by moderate differences, which are common in measured samples. The other shapes require a gap of 3.6 inches between the ends or 9–10 inches between an end and the waist; rectangle is everything inside those gaps. In the ANSUR II sample of 1,986 women, run through the rules with the high hip unknown, 46.6% of records returned rectangle. ANSUR records chest rather than bust and a navel-level waist rather than the narrowest point, and the sample is Army personnel, so the figure describes that experiment rather than women in general.

Living near four boundaries

Rectangle touches more shapes than any other: pear and inverted triangle at 3.6 inches of bust–hip difference, hourglass at the 9- and 10-inch waist cut-offs, and oval where the waist overtakes the hips. In our ANSUR II stability analysis, transitions out of Rectangle — to Triangle, and to the undetermined high-hip zone — were the most frequent single-measurement flips, and the bust was most often the deciding measurement. When the calculator reports rectangle with a boundary note, the note says which single measurement, changed by how much, would produce a different result.

Names

Banana, straight, athletic and H-shape all refer to this relationship. Athletic is the one to be careful with: it implies muscle, which the rules do not measure. A rectangle is a set of three circumferences within a narrow range of one another, whatever produces them.

What the label does not mean

It does not mean flat, shapeless or “no waist”. It means the waist is smaller than bust and hips by less than the rule’s cut-off. Many rectangle results have a visibly smaller waist; the rule simply asks for a larger drop than most bodies have. The outfits page lists options for marking a waist if that is wanted, and equally for leaving the line as it is.

• Styling direction: rectangle outfits
• On the boundary: pear vs rectangle · apple vs rectangle
• Why 2 cm matters: how to measure

References

The rules and figures on this page come from the sources below. Reference values are conventions from the literature, not targets.

1. Simmons, Istook & Devarajan (2004). Female Figure Identification Technique (FFIT) for Apparel, Part I: Describing Female ShapesJournal of Textile and Apparel, Technology and Management 4(1):1–16 · JTATM 4(1)Defines the nine FFIT shapes (hourglass, top and bottom hourglass, spoon, triangle, inverted triangle, rectangle, diamond, oval) from bust, waist, high-hip and hip circumferences on 3D body scans of North American women. The rules on this site are this set, as later revised.
2. Sokolowski (2020). Modification of the Female Figure Identification Technique (FFIT) Formulas to Include Plus Size Bodies3DBODY.TECH 2020 Conference Proceedings · proc.3dbody.tech/2020Shows the 2007 FFIT formulas assumed the waist is smaller than the bust and so failed on many larger bodies; adds the Diamond and Oval rules and a ≥ 0 lower bound to Triangle, Inverted Triangle and Rectangle. This site uses the revised formulas.