Calculate Hotel Emissions

<span class="api-method api-method-get">GET</span> /v1/hotel/emissions

Calculate CO2e emissions for a hotel stay based on country-specific factors.

Request

Required Parameters

Optional Parameters

Response

{
  "data": {
    "type": "hotel_emission",
    "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "attributes": {
      "emissions": {
        "co2e": 94.5,
        "co2e_unit": "kg",
        "co2e_calculation_method": "ipcc_ar6_gwp100",
        "co2e_grams": 94500,
        "per_night_kg": 31.5,
        "per_night_g": 31500,
        "per_room_night_kg": 31.5,
        "per_room_night_g": 31500,
        "breakdown": {
          "energy": 75.6,
          "water": 9.45,
          "waste": 9.45
        },
        "equivalents": {
          "trees_yearly": {
            "value": 4.5,
            "label": "trees needed to absorb this CO2 in a year"
          },
          "driving_km": {
            "value": 556.2,
            "label": "km driven in an average car"
          }
        },
        "source_trail": [
          {
            "data_category": "emission_factor",
            "name": "Hotel stay - United Kingdom",
            "source": "DEFRA",
            "source_dataset": "Greenhouse gas reporting: conversion factors 2025",
            "original_data": "Cornell Hotel Sustainability Benchmarking Index",
            "year": "2025",
            "region": "GB",
            "region_name": "United Kingdom"
          }
        ]
      },
      "stay": {
        "country_code": "GB",
        "country_name": "United Kingdom",
        "nights": 3,
        "rooms": 1,
        "total_room_nights": 3
      },
      "factor": {
        "value": 31.5,
        "unit": "kg CO2e per room per night",
        "is_estimate": false,
        "region": "Western Europe"
      },
      "notices": []
    }
  },
  "meta": {
    "methodology": "DEFRA 2025 / Cornell CHSB Index",
    "emission_factors_year": 2025,
    "standards_compliance": {
      "GHG_Protocol": "Scope 3 Category 6 (Business Travel)"
    },
    "calculated_at": "2026-02-07T14:30:00Z"
  }
}

Response Fields

emissions

stay

factor

notices

When using regional estimates, a notice is included:

{
  "notices": [
    {
      "message": "Using Middle East regional average for United Arab Emirates. Country-specific data not available.",
      "code": "regional_estimate",
      "severity": "info"
    }
  ]
}

Examples

Basic Stay

curl "https://api.emissions.dev/v1/hotel/emissions?\
country=GB&\
nights=3" \
  -H "Authorization: Bearer em_live_xxxx"

Multiple Rooms

curl "https://api.emissions.dev/v1/hotel/emissions?\
country=US&\
nights=5&\
rooms=10" \
  -H "Authorization: Bearer em_live_xxxx"

Week-long Holiday

curl "https://api.emissions.dev/v1/hotel/emissions?\
country=ES&\
nights=7&\
rooms=1&\
equivalents=true" \
  -H "Authorization: Bearer em_live_xxxx"

Conference Booking

curl "https://api.emissions.dev/v1/hotel/emissions?\
country=DE&\
nights=3&\
rooms=50" \
  -H "Authorization: Bearer em_live_xxxx"

Code Examples

JavaScript

const response = await fetch(
  'https://api.emissions.dev/v1/hotel/emissions?' + new URLSearchParams({
    country: 'GB',
    nights: 3,
    rooms: 1
  }),
  {
    headers: {
      'Authorization': `Bearer ${process.env.EMISSIONS_API_KEY}`
    }
  }
);

const data = await response.json();
const emissions = data.data.attributes.emissions;

console.log(`Total: ${emissions.co2e} kg CO2e`);
console.log(`Per night: ${emissions.per_room_night_kg} kg CO2e`);

Python

import requests

response = requests.get(
    'https://api.emissions.dev/v1/hotel/emissions',
    params={
        'country': 'GB',
        'nights': 3,
        'rooms': 1
    },
    headers={
        'Authorization': f'Bearer {api_key}'
    }
)

data = response.json()
emissions = data['data']['attributes']['emissions']

print(f"Total: {emissions['co2e']} kg CO2e")
print(f"Per night: {emissions['per_room_night_kg']} kg CO2e")

PHP

$response = Http::withToken($apiKey)
    ->get('https://api.emissions.dev/v1/hotel/emissions', [
        'country' => 'GB',
        'nights' => 3,
        'rooms' => 1,
    ]);

$data = $response->json();
$emissions = $data['data']['attributes']['emissions'];

echo "Total: {$emissions['co2e']} kg CO2e\n";
echo "Per night: {$emissions['per_room_night_kg']} kg CO2e\n";

Complete Trip Emissions

Combine with the Travel API for full business trip emissions. Both endpoints report GHG Protocol Scope 3 Category 6.

// Complete trip: London → Dubai, 4 nights
const [travel, hotel] = await Promise.all([
  fetch('https://api.emissions.dev/v1/travel/emissions?' + new URLSearchParams({
    origin_country: 'GB',
    origin_location: 'London',
    destination_country: 'AE',
    destination_location: 'Dubai',
    transport_mode: 'flight',
    return_trip: true
  }), { headers: { 'Authorization': `Bearer ${apiKey}` } }),

  fetch('https://api.emissions.dev/v1/hotel/emissions?' + new URLSearchParams({
    country: 'AE',
    nights: 4
  }), { headers: { 'Authorization': `Bearer ${apiKey}` } })
]);

const t = (await travel.json()).data.attributes.emissions;
const h = (await hotel.json()).data.attributes.emissions;

// Flights: 1,247 kg + Hotel: 290 kg = Total: 1,537 kg
console.log(`Total trip: ${t.co2e + h.co2e} kg CO2e`);

Errors

Invalid Country

{
  "error": {
    "code": "invalid_country",
    "message": "Country code 'XX' not recognised. Use ISO 3166-1 alpha-2 codes (e.g., GB, US, FR).",
    "status": 422
  }
}

Invalid Nights

{
  "error": {
    "code": "validation_error",
    "message": "The nights field must be between 1 and 365.",
    "field": "nights",
    "status": 422
  }
}

Too Many Rooms

{
  "error": {
    "code": "validation_error",
    "message": "The rooms field must not be greater than 100.",
    "field": "rooms",
    "status": 422
  }
}