Body Fat Calculator API

POST https://api.findutils.com/api/tools/body-fat-calculator/execute

Estimate body fat percentage, fat mass, lean mass, BMI, and a body-composition category. Four methods: the U.S. Navy circumference method (waist, neck, hip), a BMI-based estimate (Deurenberg), and the Jackson-Pollock 3-site and 7-site skinfold equations with Siri conversion. Metric (kg/cm) or imperial (lbs/in) inputs; skinfolds are always millimetres.

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Request body

application/json

gender

string required

Biological sex used by the formulas. One of male · female.
weight

number required

Body weight in kg (metric) or lbs (imperial).
height

number required

Height in cm (metric) or inches (imperial).
unit_system

string optional

Unit system for all measurements. One of metric · imperial. Default "metric".
method

string optional

"navy" = U.S. Navy circumference method (needs waist, neck, and hip for female). "bmi" = BMI-based estimate (Deurenberg). "jackson_pollock_3" / "jackson_pollock_7" = skinfold caliper methods; see the skinfold args for which sites each one needs. One of navy · bmi · jackson_pollock_3 · jackson_pollock_7. Default "navy".
waist

number optional

Waist circumference at the navel (cm or in). Required for the navy method.
neck

number optional

Neck circumference below the larynx (cm or in). Required for the navy method.
hip

number optional

Hip circumference at the widest point (cm or in). Required for the navy method when gender is female.
age

integer optional

Age in years. Used by the bmi and jackson_pollock methods. Default 30. Default 30.
chest

number optional

Chest skinfold in mm. Jackson-Pollock: 3-site (male) and 7-site.
abdomen

number optional

Abdominal skinfold in mm. Jackson-Pollock: 3-site (male) and 7-site.
thigh

number optional

Thigh skinfold in mm. Jackson-Pollock: 3-site (both) and 7-site.
triceps

number optional

Triceps skinfold in mm. Jackson-Pollock: 3-site (female) and 7-site.
suprailiac

number optional

Suprailiac skinfold in mm. Jackson-Pollock: 3-site (female) and 7-site.
subscapular

number optional

Subscapular skinfold in mm. Jackson-Pollock 7-site only.
midaxillary

number optional

Midaxillary skinfold in mm. Jackson-Pollock 7-site only.

Example arguments

Verified

{
  "gender": "male",
  "weight": 70,
  "height": 175,
  "waist": 85,
  "neck": 38
}

curl -X POST https://api.findutils.com/api/tools/body-fat-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "gender": "male",
    "weight": 70,
    "height": 175,
    "waist": 85,
    "neck": 38
  }'

const response = await fetch('https://api.findutils.com/api/tools/body-fat-calculator/execute', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({"gender":"male","weight":70,"height":175,"waist":85,"neck":38}),
});
const data = await response.json();

import requests

response = requests.post(
    "https://api.findutils.com/api/tools/body-fat-calculator/execute",
    json={"gender":"male","weight":70,"height":175,"waist":85,"neck":38},
)
data = response.json()

$ch = curl_init('https://api.findutils.com/api/tools/body-fat-calculator/execute');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"gender":"male","weight":70,"height":175,"waist":85,"neck":38}',
    CURLOPT_RETURNTRANSFER => true,
]);
$data = json_decode(curl_exec($ch), true);

Also an MCP tool

Call body_fat_calculator from Claude, Cursor or any MCP client. Same arguments, same output.

https://mcp.findutils.com

MCP reference

Rate limit: 60 a minute, per IP
Auth: None
REST id: body-fat-calculator
MCP name: body_fat_calculator
Category: Calculators
Machine-readable: openapi.json · markdown.md

Request body

Example arguments

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