Website Carbon Calculator

Estimate the carbon footprint of any web page. Calculates CO2 emissions per page view based on page weight, hosting, and resource analysis.

What does Website Carbon Calculator do?

This actor analyzes web pages and estimates their carbon footprint based on page weight, resource count, compression, and hosting provider. It calculates CO2 emissions per view, per 1,000 views, and projected annual emissions. It also provides a letter grade from A+ to F, actionable recommendations for reducing emissions, and comparison against the web average. Use it to audit your site's environmental impact, generate sustainability reports, or benchmark against competitors.

Use cases

• Sustainability managers -- measure and track website carbon emissions over time for ESG and corporate social responsibility reporting
• Green web designers -- identify heavy pages and optimize for lower emissions during redesigns and performance sprints
• SEO specialists -- lighter pages load faster and rank better; carbon data doubles as a performance indicator
• Agency teams -- show clients the environmental impact of their website with concrete numbers and letter grades
• Competitive analysts -- compare carbon footprint with competitor sites to highlight your green advantage in proposals
• Compliance teams -- generate documentation for environmental regulations that require digital carbon footprint disclosure

Why use Website Carbon Calculator?

• Batch processing -- analyze hundreds of pages in a single run instead of testing them one at a time
• Comprehensive metrics -- returns CO2 per view, per 1,000 views, annual projections, and a letter grade
• Actionable recommendations -- provides specific suggestions to reduce emissions for each page
• Green hosting detection -- automatically checks whether the hosting provider uses renewable energy
• Structured JSON output -- clean, consistent data ready for dashboards, reports, and spreadsheets
• Pay-per-event pricing -- you only pay for the pages you analyze, starting at $0.001 per URL

Input parameters

Parameter	Type	Required	Default	Description
urls	array	Yes	--	List of web page URLs to calculate carbon footprint for

Provide any publicly accessible web page URL. Each page is analyzed independently for page weight, compression, resource breakdown, and hosting provider.

Input example

{
    "urls": [
        "https://www.google.com",
        "https://www.apple.com",
        "https://en.wikipedia.org"
    ]
}

Output example

{
    "url": "https://www.google.com",
    "pageSizeBytes": 245000,
    "pageSizeKb": 239,
    "adjustedSizeBytes": 183750,
    "greenHosting": true,
    "co2PerView": 0.000138,
    "co2Per1000Views": 0.138,
    "co2PerYearAt10kMonthly": 16.56,
    "grade": "A+",
    "lighterThanPercent": 95,
    "scriptSizeBytes": 45000,
    "styleSizeBytes": 12000,
    "imageSizeEstimateBytes": 80000,
    "htmlSizeBytes": 108000,
    "isCompressed": true,
    "recommendations": [],
    "error": null,
    "checkedAt": "2026-03-01T12:00:00.000Z"
}

How much does it cost?

Website Carbon Calculator uses Apify's pay-per-event pricing model. You are only charged for what you use.

Event	Price	Description
Start	$0.035	One-time per run
URL analyzed	$0.001	Per page analyzed

Cost examples:

• Analyzing 10 pages: $0.035 + (10 x $0.001) = $0.045
• Analyzing 100 pages: $0.035 + (100 x $0.001) = $0.135
• Analyzing 1,000 pages: $0.035 + (1,000 x $0.001) = $1.035

Using the Apify API

You can call Website Carbon Calculator programmatically from any language using the Apify API. The actor slug is automation-lab/website-carbon-calculator. Below are examples for the two most common languages.

Node.js

import { ApifyClient } from 'apify-client';

const client = new ApifyClient({ token: 'YOUR_TOKEN' });
const run = await client.actor('automation-lab/website-carbon-calculator').call({
    urls: ['https://www.google.com', 'https://www.apple.com'],
});
const { items } = await client.dataset(run.defaultDatasetId).listItems();
console.log(items);

Python

from apify_client import ApifyClient

client = ApifyClient('YOUR_TOKEN')
run = client.actor('automation-lab/website-carbon-calculator').call(run_input={
    'urls': ['https://www.google.com', 'https://www.apple.com'],
})
items = client.dataset(run['defaultDatasetId']).list_items().items
print(items)

Integrations

Website Carbon Calculator integrates with the major automation and data platforms through the Apify ecosystem:

• Make (formerly Integromat) -- run carbon audits on a schedule and route results to reporting tools or sustainability dashboards.
• Zapier -- create Zaps that automatically analyze new pages and send carbon reports to stakeholders.
• Google Sheets -- export results for ongoing tracking, trend analysis, and executive sustainability reports.
• Slack -- send alerts when a page exceeds a carbon threshold or when a grade drops below acceptable levels.
• Webhooks -- trigger downstream processing in your own systems when analysis completes.
• n8n -- orchestrate runs from n8n workflows or any platform that supports HTTP requests and the Apify REST API.

Tips and best practices

• Focus on your heaviest pages first -- sort results by pageSizeBytes descending to find the biggest optimization opportunities.
• Track grades over time -- schedule weekly runs and monitor the grade field to see if your optimizations are making a difference.
• Enable compression -- pages with isCompressed: false are low-hanging fruit; enabling gzip or brotli can cut emissions significantly.
• Reduce image weight -- the imageSizeEstimateBytes field often reveals the largest contributor to page weight and carbon emissions.
• Use green hosting -- switching to a renewable-energy hosting provider instantly improves your carbon grade.
• Include all key pages -- analyze your homepage, top landing pages, and heaviest content pages to get a representative picture of your site's overall footprint.

FAQ

How is the CO2 calculated? The actor uses a methodology based on page weight, similar to the Website Carbon Calculator (websitecarbon.com). It factors in data transfer energy, hosting type (green vs. standard), and returning visitor caching to estimate grams of CO2 per page view.

Does the actor render JavaScript? No. It fetches the raw HTML and estimates resource sizes from the document source. This provides fast, cost-effective analysis suitable for bulk auditing. For pixel-perfect rendering analysis, pair it with a browser-based performance tool.

What does the grade mean? Grades range from A+ (cleanest) to F (heaviest). An A+ page is lighter than 95% of web pages tested. The lighterThanPercent field gives you the exact percentile ranking.

How is green hosting detected? The actor checks the hosting provider against The Green Web Foundation's database of verified green hosts. If the server IP resolves to a provider that uses renewable energy, greenHosting returns true.

Can I use this for regulatory compliance? The results provide useful estimates for sustainability reporting and internal audits. However, for formal regulatory submissions, you should verify the methodology meets your jurisdiction's specific requirements and standards.