{
  "id": "body-fat-calculator",
  "version": "2.0.0",
  "name": "Body Fat Calculator",
  "shortName": "Body Fat",
  "description": "Estimate body-fat percentage with the U.S. Navy circumference method and compare it with a BMI-based estimate.",
  "category": "Health & Fitness",
  "categorySlug": "health-fitness",
  "keywords": [
    "body fat percentage",
    "US Navy method",
    "fat mass",
    "lean mass",
    "body composition"
  ],
  "status": "live",
  "workStatus": "pending",
  "reviewStatus": "pending",
  "migrationStatus": "migrated",
  "migratedDate": "2026-08-25",
  "engine": "native",
  "creator": null,
  "reviewer": null,
  "quality": {
    "availability": "live",
    "technicalReviewRecord": "/reviews/body-fat-calculator.json",
    "qualifiedReview": "pending",
    "qualifiedReviewer": null,
    "qualifiedReviewDate": null,
    "formulaVersion": "2.0.0",
    "referenceCoverage": "references-listed",
    "releaseTestScope": "Catalog and regression checks are not a professional formula audit; consult release evidence.",
    "historicalMetadataDate": "2026-08-25",
    "historicalMetadataNotice": "The imported date is not evidence of a completed human review."
  },
  "notice": "Circumference methods estimate body composition and are not diagnostic measurements.",
  "urls": {
    "page": "/calculator/body-fat-calculator/",
    "definition": "/calculator/body-fat-calculator/definition.json",
    "schema": "/calculator/body-fat-calculator/schema.json",
    "llms": "/calculator/body-fat-calculator/llms.txt",
    "legacyDefinition": "/calculator/body-fat-calculator.json"
  },
  "queryExample": "https://askcalculators.com/calculator/body-fat-calculator/?unitSystem=metric&sex=male&age=30&weightKg=80&heightCm=180&neckCm=39&waistCm=90&hipCm=100",
  "queryParameters": {
    "unitSystem": {
      "label": "Units",
      "type": "select",
      "required": true,
      "default": "metric"
    },
    "sex": {
      "label": "Sex used by equation",
      "type": "select",
      "required": true,
      "default": "male"
    },
    "age": {
      "label": "Age",
      "type": "number",
      "required": true,
      "default": 30
    },
    "weightKg": {
      "label": "Weight",
      "type": "number",
      "required": true,
      "default": 80,
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      }
    },
    "heightCm": {
      "label": "Height",
      "type": "number",
      "required": true,
      "default": 180,
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      }
    },
    "neckCm": {
      "label": "Neck circumference",
      "type": "number",
      "required": true,
      "default": 39,
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      }
    },
    "waistCm": {
      "label": "Waist circumference",
      "type": "number",
      "required": true,
      "default": 90,
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      }
    },
    "hipCm": {
      "label": "Hip circumference (used for female equation)",
      "type": "number",
      "required": true,
      "default": 100,
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      }
    },
    "weightLb": {
      "label": "Weight",
      "type": "number",
      "required": true,
      "default": 176,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    },
    "feet": {
      "label": "Height feet",
      "type": "number",
      "required": true,
      "default": 5,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    },
    "inches": {
      "label": "Height inches",
      "type": "number",
      "required": true,
      "default": 11,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    },
    "neckIn": {
      "label": "Neck circumference",
      "type": "number",
      "required": true,
      "default": 15.4,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    },
    "waistIn": {
      "label": "Waist circumference",
      "type": "number",
      "required": true,
      "default": 35.4,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    },
    "hipIn": {
      "label": "Hip circumference (used for female equation)",
      "type": "number",
      "required": true,
      "default": 39.4,
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      }
    }
  },
  "inputs": [
    {
      "id": "unitSystem",
      "label": "Units",
      "type": "select",
      "required": true,
      "defaultValue": "metric",
      "options": [
        {
          "label": "Metric",
          "value": "metric"
        },
        {
          "label": "Imperial",
          "value": "imperial"
        }
      ],
      "width": "full"
    },
    {
      "id": "sex",
      "label": "Sex used by equation",
      "type": "select",
      "required": true,
      "defaultValue": "male",
      "options": [
        {
          "label": "Male",
          "value": "male"
        },
        {
          "label": "Female",
          "value": "female"
        }
      ],
      "width": "half"
    },
    {
      "id": "age",
      "label": "Age",
      "type": "number",
      "required": true,
      "defaultValue": 30,
      "min": 18,
      "max": 100,
      "step": 1,
      "suffix": "years",
      "width": "half"
    },
    {
      "id": "weightKg",
      "label": "Weight",
      "type": "number",
      "required": true,
      "defaultValue": 80,
      "min": 1,
      "max": 500,
      "step": 0.1,
      "suffix": "kg",
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      },
      "width": "half"
    },
    {
      "id": "heightCm",
      "label": "Height",
      "type": "number",
      "required": true,
      "defaultValue": 180,
      "min": 50,
      "max": 300,
      "step": 0.1,
      "suffix": "cm",
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      },
      "width": "half"
    },
    {
      "id": "neckCm",
      "label": "Neck circumference",
      "type": "number",
      "required": true,
      "defaultValue": 39,
      "min": 10,
      "max": 100,
      "step": 0.1,
      "suffix": "cm",
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      },
      "width": "half"
    },
    {
      "id": "waistCm",
      "label": "Waist circumference",
      "type": "number",
      "required": true,
      "defaultValue": 90,
      "min": 20,
      "max": 300,
      "step": 0.1,
      "suffix": "cm",
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      },
      "width": "half"
    },
    {
      "id": "hipCm",
      "label": "Hip circumference (used for female equation)",
      "type": "number",
      "required": true,
      "defaultValue": 100,
      "min": 20,
      "max": 300,
      "step": 0.1,
      "suffix": "cm",
      "showWhen": {
        "field": "unitSystem",
        "equals": "metric"
      },
      "width": "full"
    },
    {
      "id": "weightLb",
      "label": "Weight",
      "type": "number",
      "required": true,
      "defaultValue": 176,
      "min": 2,
      "max": 1100,
      "step": 0.1,
      "suffix": "lb",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "full"
    },
    {
      "id": "feet",
      "label": "Height feet",
      "type": "number",
      "required": true,
      "defaultValue": 5,
      "min": 1,
      "max": 9,
      "step": 1,
      "suffix": "ft",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "half"
    },
    {
      "id": "inches",
      "label": "Height inches",
      "type": "number",
      "required": true,
      "defaultValue": 11,
      "min": 0,
      "max": 11.9,
      "step": 0.1,
      "suffix": "in",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "half"
    },
    {
      "id": "neckIn",
      "label": "Neck circumference",
      "type": "number",
      "required": true,
      "defaultValue": 15.4,
      "min": 4,
      "max": 40,
      "step": 0.1,
      "suffix": "in",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "half"
    },
    {
      "id": "waistIn",
      "label": "Waist circumference",
      "type": "number",
      "required": true,
      "defaultValue": 35.4,
      "min": 8,
      "max": 120,
      "step": 0.1,
      "suffix": "in",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "half"
    },
    {
      "id": "hipIn",
      "label": "Hip circumference (used for female equation)",
      "type": "number",
      "required": true,
      "defaultValue": 39.4,
      "min": 8,
      "max": 120,
      "step": 0.1,
      "suffix": "in",
      "showWhen": {
        "field": "unitSystem",
        "equals": "imperial"
      },
      "width": "full"
    }
  ],
  "outputs": [
    {
      "id": "bodyFat",
      "label": "Navy body-fat estimate",
      "format": "percent",
      "primary": true,
      "digits": 1
    },
    {
      "id": "category",
      "label": "Body-fat category",
      "format": "text"
    },
    {
      "id": "bmiEstimate",
      "label": "BMI-based estimate",
      "format": "percent",
      "digits": 1
    },
    {
      "id": "fatMass",
      "label": "Estimated fat mass",
      "format": "text"
    },
    {
      "id": "leanMass",
      "label": "Estimated lean mass",
      "format": "text"
    },
    {
      "id": "bmi",
      "label": "BMI",
      "format": "number",
      "digits": 1
    }
  ],
  "formula": {
    "expression": "U.S. Navy circumference equations use log10 of height and sex-specific circumference combinations; BMI estimate = 1.2×BMI + 0.23×age − 10.8×male − 5.4."
  },
  "examples": [
    {
      "label": "Reproducible default-input example (not a personal recommendation)",
      "inputs": {
        "unitSystem": "metric",
        "sex": "male",
        "age": 30,
        "weightKg": 80,
        "heightCm": 180,
        "neckCm": 39,
        "waistCm": 90,
        "hipCm": 100,
        "weightLb": 176,
        "feet": 5,
        "inches": 11,
        "neckIn": 15.4,
        "waistIn": 35.4,
        "hipIn": 39.4
      }
    }
  ],
  "sources": [
    {
      "label": "Calculator.net reference calculator",
      "url": "https://www.calculator.net/body-fat-calculator.html"
    }
  ]
}