{
  "id": "body-shape",
  "version": "ea21ac062f90",
  "status": "published",
  "name": "Body Shape Calculator",
  "question": "What is my body shape?",
  "summary": "Sorts bust, waist, high hip, and hip measurements into one of seven body shapes (hourglass, bottom hourglass, top hourglass, spoon, triangle, inverted triangle, rectangle) with the Female Figure Identification Technique (FFIT) rules.",
  "category": "health",
  "subcategory": "body",
  "url": "https://www.acalculator.org/health/body-shape-calculator",
  "markdown": "https://www.acalculator.org/health/body-shape-calculator.md",
  "kind": "function",
  "method": "FFIT rules on inch differences, checked in order: hourglass, bottom hourglass, top hourglass, spoon, triangle, inverted triangle, rectangle; the first match is the shape.",
  "assumptions": [
    "The rules are the FFIT formulas for apparel (Simmons, Istook and Devarajan 2004; formulas as published by Lee and others 2007), in inches; centimetres are converted with 1 in = 2.54 cm.",
    "The shapes are checked in order and the first rule that holds wins, because some rules overlap.",
    "FFIT was made from 3D body scans of women for clothing fit. It describes proportions, not health.",
    "Measurements with a much larger waist than bust or hips may match no shape; FFIT’s oval and diamond shapes need stomach and abdomen measurements."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "bust": {
        "title": "Bust",
        "description": "Around the fullest part of the bust.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.25,
        "maximum": 3
      },
      "waist": {
        "title": "Waist",
        "description": "Around the narrowest part of the waist.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.25,
        "maximum": 3
      },
      "highHip": {
        "title": "High hip",
        "description": "Around the top of the hip bones, between the waist and the hips.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.25,
        "maximum": 3
      },
      "hips": {
        "title": "Hips",
        "description": "Around the widest part of the hips and buttocks.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.25,
        "maximum": 3
      }
    }
  },
  "outputs": {
    "shape": {
      "label": "Your body shape",
      "description": "The first FFIT shape whose rule the measurements meet.",
      "format": "text"
    },
    "about": {
      "label": "Meaning",
      "description": "A one-line description of the shape.",
      "format": "text"
    },
    "bustHip": {
      "label": "Bust minus hips",
      "description": "Bust circumference minus hip circumference, in inches.",
      "format": "quantity",
      "unit": "in"
    },
    "bustWaist": {
      "label": "Bust minus waist",
      "description": "Bust circumference minus waist circumference, in inches.",
      "format": "quantity",
      "unit": "in"
    },
    "hipWaist": {
      "label": "Hips minus waist",
      "description": "Hip circumference minus waist circumference, in inches.",
      "format": "quantity",
      "unit": "in"
    },
    "shelf": {
      "label": "High hip ÷ waist",
      "description": "High hip circumference divided by waist circumference; 1.193 or more marks a high-hip “shelf”.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "bust": 0.9144,
      "waist": 0.7111999999999999,
      "highHip": 0.8635999999999999,
      "hips": 0.9652
    },
    "outputs": {
      "shape": "Hourglass",
      "about": "Bust and hips about the same, with a clearly defined waist.",
      "bustHip": -0.050799999999999956,
      "bustWaist": 0.20320000000000005,
      "hipWaist": 0.254,
      "shelf": 1.2142857142857142
    },
    "text": "With bust 36 in, waist 28 in, and hips 38 in, your body shape is Hourglass."
  },
  "examples": [
    {
      "given": {
        "bust": 0.9144,
        "waist": 0.7111999999999999,
        "highHip": 0.8635999999999999,
        "hips": 0.9652
      },
      "expect": {
        "shape": "Hourglass",
        "about": "Bust and hips about the same, with a clearly defined waist.",
        "hipWaist": 0.254,
        "bustWaist": 0.2032
      },
      "source": "FFIT rules (Lee and others 2007, as printed in Sokolowski and others 2020, Table 7); the shape sentences are listed in content.mdx; hand calculation in content.mdx: bust − hips = −2 ≤ 1, hips − bust = 2 < 3.6, hips − waist = 10 ≥ 10"
    },
    {
      "given": {
        "bust": 0.8635999999999999,
        "waist": 0.6858,
        "highHip": 0.7874,
        "hips": 1.016
      },
      "expect": {
        "shape": "Bottom hourglass",
        "about": "Hips larger than the bust, with a clearly defined waist.",
        "shelf": 1.1481481481481481
      },
      "source": "FFIT rules; hand calculation in content.mdx: hips − bust = 6, hips − waist = 13, high hip ÷ waist = 1.148 < 1.193"
    },
    {
      "given": {
        "bust": 0.8635999999999999,
        "waist": 0.7111999999999999,
        "highHip": 0.9144,
        "hips": 1.016
      },
      "expect": {
        "shape": "Spoon",
        "about": "Hips much larger than the bust, with a “shelf” at the high hip.",
        "shelf": 1.2857142857142858
      },
      "source": "FFIT rules; hand calculation in content.mdx: hips − bust = 6 > 2, hips − waist = 12 ≥ 7, high hip ÷ waist = 1.286 ≥ 1.193"
    },
    {
      "given": {
        "bust": 0.8635999999999999,
        "waist": 0.8128,
        "highHip": 0.9144,
        "hips": 1.016
      },
      "expect": {
        "shape": "Triangle",
        "about": "Hips larger than the bust, without a clearly defined waist."
      },
      "source": "FFIT rules; hand calculation in content.mdx: hips − bust = 6 ≥ 3.6 and hips − waist = 8 < 9"
    },
    {
      "given": {
        "bust": 1.016,
        "waist": 0.8382,
        "highHip": 0.8635999999999999,
        "hips": 0.889
      },
      "expect": {
        "shape": "Inverted triangle",
        "about": "Bust larger than the hips, without a clearly defined waist."
      },
      "source": "FFIT rules; hand calculation in content.mdx: bust − hips = 5 ≥ 3.6 and bust − waist = 7 < 9"
    },
    {
      "given": {
        "bust": 1.016,
        "waist": 0.7365999999999999,
        "highHip": 0.8635999999999999,
        "hips": 0.9144
      },
      "expect": {
        "shape": "Top hourglass",
        "about": "Bust larger than the hips, with a clearly defined waist."
      },
      "source": "FFIT rules; hand calculation in content.mdx: bust − hips = 4 (over 1, under 10) and bust − waist = 11 ≥ 9"
    },
    {
      "given": {
        "bust": 0.889,
        "waist": 0.762,
        "highHip": 0.8635999999999999,
        "hips": 0.9144
      },
      "expect": {
        "shape": "Rectangle",
        "about": "Bust and hips about the same, without a clearly defined waist."
      },
      "source": "FFIT rules; hand calculation in content.mdx: bust and hips 1 in apart, bust − waist = 5 < 9, hips − waist = 6 < 10"
    }
  ],
  "sources": [
    "Simmons KP, Istook CL, Devarajan P. Female Figure Identification Technique (FFIT) for apparel, part I: describing female shapes. Journal of Textile and Apparel, Technology and Management 2004;4(1):1–16.",
    "Lee JY, Istook CL, Nam YJ, Park SM. Comparison of body shape between USA and Korean women. International Journal of Clothing Science and Technology 2007;19(5):374–391. doi:10.1108/09556220710819555",
    "Sokolowski SL, Bettencourt C. Modification of the Female Figure Identification Technique (FFIT) formulas to include plus size bodies. Proceedings of 3DBODY.TECH 2020, Table 7 (original FFIT formulas, in inches). doi:10.15221/20.22",
    "NIST SP 811 (2008), Appendix B: 1 in = 2.54 cm exactly."
  ],
  "related": [
    "ideal-weight",
    "bmi"
  ],
  "changelog": [
    {
      "date": "2026-09-28",
      "note": "The answer reads “With bust …, waist …, and hips …”; the description row is labelled Meaning."
    },
    {
      "date": "2026-09-28",
      "note": "Examples also check the one-line description of each shape."
    }
  ]
}