Free Health Calculator API | HealthCalcsHub Developer Docs

Authentication

This API is completely free with no API key or account required. Just make requests.

✓

No API key needed. All endpoints are public and free. We ask only that you include a small attribution link on pages where you use our calculators — this is how we keep the API free forever.

ℹ

Rate limit: 200 requests/minute per IP. For higher limits, contact us.

Base URL

All API endpoints are available under the following base URL.

BASE URL https://healthcalcshub.com/api/v1

Available Calculators

All calculators support English, Hindi (hi), and Arabic (ar) response labels via the lang parameter.

⚖

BMI Calculator

/api/v1/bmi

Body Mass Index with WHO classification and health risk level.

🔥

TDEE Calculator

/api/v1/tdee

Total Daily Energy Expenditure with 5 activity levels.

📊

Body Fat %

/api/v1/bodyfat

Body fat percentage via Navy method with category.

🏋

Ideal Weight

/api/v1/idealweight

4 formulas: Devine, Robinson, Miller, Hamwi.

💪

Lean Body Mass

/api/v1/lbm

Lean mass, fat mass, and muscle percentage breakdown.

🥗

Calorie Needs

/api/v1/calories

Daily calories for loss, maintenance, and gain goals.

🥩

Protein Intake

/api/v1/protein

Optimal daily protein range based on weight and goal.

💧

Water Intake

/api/v1/water

Daily water requirements including exercise adjustment.

📐

Macros Split

/api/v1/macros

Carb, protein, and fat grams for any calorie target.

BMI Calculator

Calculate Body Mass Index and receive WHO classification.

GET /api/v1/bmi Calculate BMI score and category ▼

Parameters

Parameter	Type	Required	Description
weight	number	Required	Weight in kilograms (e.g. 70)
height	number	Required	Height in centimeters (e.g. 175)
unit	string	Optional	`metric` (default) or `imperial`
lang	string	Optional	`en` (default), `hi`, `ar`

# GET request — no auth required
curl "https://healthcalcshub.com/api/v1/bmi?weight=70&height=175&lang=en"

200 OK

{
  "success": true,
  "calculator": "bmi",
  "inputs": { "weight_kg": 70, "height_cm": 175 },
  "result": {
    "bmi": 22.9,
    "category": "Normal weight",
    "healthy_range": { "min": 18.5, "max": 24.9 },
    "risk": "Low"
  },
  "attribution": "Powered by healthcalcshub.com"
}

TDEE Calculator

Total Daily Energy Expenditure with BMR and goal-based calorie targets.

GET /api/v1/tdee Total Daily Energy Expenditure ▼

Parameter	Type	Required	Description
weight	number	Required	Weight in kg
height	number	Required	Height in cm
age	number	Required	Age in years
gender	string	Required	`male` or `female`
activity	string	Required	sedentary · light · moderate · active · very_active

curl "https://healthcalcshub.com/api/v1/tdee?weight=75&height=180&age=28&gender=male&activity=moderate"

200 OK

{
  "success": true,
  "result": {
    "bmr": 1847, "tdee": 2866,
    "goals": { "weight_loss": 2366, "maintenance": 2866, "muscle_gain": 3116 }
  }
}

Water Intake

Daily water requirements adjusted for activity level and climate.

GET /api/v1/water Daily water intake recommendation ▼

Parameter	Type	Required	Description
weight	number	Required	Weight in kg
activity	string	Optional	sedentary (default) · light · moderate · active
climate	string	Optional	`temperate` (default) or `hot`

curl "https://healthcalcshub.com/api/v1/water?weight=70&activity=moderate&climate=hot"

200 OK

{
  "success": true,
  "result": {
    "daily_liters": 3.2, "daily_ml": 3200, "glasses_8oz": 14,
    "breakdown": { "base": 2400, "activity_add": 400, "climate_add": 400 }
  }
}

Live API Tester

Try the API right now — no account, no setup.

▶ BMI API — Live Test

Fill in the fields and hit Run to see a real API response.

Weight (kg)

Height (cm)

Language

GET https://healthcalcshub.com/api/v1/bmi?weight=70&height=175&lang=en

// Response will appear here...

Attribution (Required)

In exchange for free API access, please include a small attribution link on any page using our calculators.

Why attribution?

Attribution keeps this API free forever. A single "Powered by" link on your page is all we ask — no payment, no account, no strings attached.

<p>Powered by <a href="https://healthcalcshub.com" target="_blank">HealthCalcsHub</a></p>

🔗

The attribution link acts as a dofollow backlink — it also improves your site's perceived credibility by linking to a well-established health resource.

Code Examples

Copy-paste ready snippets for the most common languages.

JavaScript (fetch)

// Fetch BMI data and display on your page
const getBMI = async (weight, height) => {
  const res = await fetch(
    `https://healthcalcshub.com/api/v1/bmi?weight=${weight}&height=${height}`
  );
  const data = await res.json();
  return data.result;
};

// Usage
getBMI(70, 175).then(result => {
  console.log(`BMI: ${result.bmi} (${result.category})`);
});

PHP

<?php
function getHealthCalc($endpoint, $params) {
  $url = "https://healthcalcshub.com/api/v1/" . $endpoint
       . "?" . http_build_query($params);
  $json = file_get_contents($url);
  return json_decode($json, true);
}
$result = getHealthCalc('bmi', ['weight' => 70, 'height' => 175, 'lang' => 'en']);
echo "BMI: " . $result['result']['bmi'];

Python

import requests

def get_bmi(weight_kg, height_cm, lang='en'):
    response = requests.get(
        "https://healthcalcshub.com/api/v1/bmi",
        params={"weight": weight_kg, "height": height_cm, "lang": lang}
    )
    return response.json()

data = get_bmi(70, 175)
print(f"BMI: {data['result']['bmi']} — {data['result']['category']}")

Error Codes

Code	Meaning	Example
400	Bad Request — missing or invalid params	"weight is required"
422	Unprocessable — value out of range	"height must be 50–300 cm"
429	Rate limit exceeded	"200 req/min limit reached"
500	Server error — please retry	"Internal server error"