Body Shape Calculator (FFIT shapes from bust, waist & hips)

Understanding the body shape calculator — concept and principle

This calculator sorts a figure into a body shape for clothing fit using the Female Figure Identification Technique (FFIT), from bust, waist, high-hip and hip measurements. It also shows the key differences and ratios the method uses. People choosing clothes, fashion students and pattern makers use it.

How it is calculated

Differences are converted to inches (1 in = 2.54 cm) and tested in this order:

• Hourglass: bust − hips ≤ 1, hips − bust < 3.6, and bust − waist ≥ 9 or hips − waist ≥ 10
• Bottom hourglass, top hourglass, spoon, triangle, inverted triangle and rectangle follow, each with its own rules on bust, waist, high hip and hips
• When the waist is larger than the hips, a 2020 extension gives diamond or oval

The page also shows bust − hips, hips − waist, bust − waist, high hip ÷ waist and waist ÷ hips.

The principle

FFIT was developed at North Carolina State University from 3D body scans to describe the proportions that matter for how clothes fit. It compares circumferences rather than absolute sizes, so two people of different sizes can share a shape. The order of tests matters, because some shapes overlap; the first rule that matches decides. Shapes describe proportions only; no shape is better or healthier than another.

Worked example

Defaults: bust 94 cm, waist 70 cm, high hip 84 cm, hips 98 cm.

1. Bust − hips = -4 cm (−1.57 in), which is ≤ 1 in, and hips − bust = 1.57 in < 3.6.
2. Bust − waist = 24 cm = 9.45 in ≥ 9; hips − waist = 28 cm.
3. High hip ÷ waist = 1.2; waist ÷ hips = 0.71.
4. The hourglass rules are met first: Hourglass.

How to read the result

Use the shape as a guide to cuts and styles that follow your proportions, for example fitted waists for hourglass shapes. Measurements change with posture and breathing, so measure relaxed and repeat if you are near a boundary.

Common mistakes

• Measuring over bulky clothes.
• Measuring the waist at the navel instead of the narrowest point.
• Holding the tape at an angle.
• Treating the shape as a health measure.

Frequently asked questions

What is an hourglass body shape?

Bust and hips nearly equal, with a waist clearly smaller than both.

Why are inches used?

The FFIT rules were published with differences in inches; the calculator converts from centimetres.

Can my shape change?

Yes, with changes in weight, muscle and age.

Sources: Simmons K, Istook CL, Devarajan P, "Female Figure Identification Technique (FFIT) for apparel, Part I", J Textile Apparel Technol Manag 2004;4(1) · Lee JY, Istook CL, Nam YJ, Park SM, "Comparison of body shape between USA and Korean women", Int J Cloth Sci Technol 2007;19(5):374–391