Body-fat % (US-Navy method) API

Estimate body-fat percentage from tape measurements via the US-Navy (Hodgdon-Beckett) circumference equations (log10 of waist/neck/height; +hip for women), with ACE category bands. Answers 'what's my body fat percentage', 'body fat from waist and neck', 'US Navy body fat calculator'.

Price$0.01per request

MethodPOST

Route/v1/health/body-fat-navy

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

healthbody-fatus-navycircumferencefitnesscompositionfatcalculator

API URLhttps://x402.hexl.dev/v1/health/body-fat-navy

Integration docs

Example request

{
  "sex": "male",
  "heightCm": 180,
  "neckCm": 40,
  "waistCm": 90
}

Example response

{
  "bodyFatPercent": 18.4,
  "category": "acceptable",
  "method": "US Navy (Hodgdon-Beckett) circumference equations",
  "sex": "male",
  "inputs": {
    "heightCm": 180,
    "neckCm": 40,
    "waistCm": 90
  }
}

Input schema

{
  "type": "object",
  "required": [
    "sex",
    "heightCm",
    "neckCm",
    "waistCm"
  ],
  "properties": {
    "sex": {
      "type": "string",
      "enum": [
        "male",
        "female"
      ]
    },
    "heightCm": {
      "type": "number",
      "examples": [
        180
      ]
    },
    "neckCm": {
      "type": "number",
      "examples": [
        40
      ]
    },
    "waistCm": {
      "type": "number",
      "examples": [
        90
      ]
    },
    "hipCm": {
      "type": "number",
      "description": "Required for female",
      "examples": [
        95
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}