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Website Carbon Footprint

Measure the ecological impact of any website via the Website Carbon API.

TL;DR:

Website carbon footprint is computed from total page weight, CO2 per byte transferred (avg 0.81g CO2/GB), and green hosting coefficient. Compared to global average. Useful for ESG reports and sustainability KPI optimisation.

CO₂ per ViewGrams of carbon per page view
Energy SourceGreen or standard hosting
Page SizeTotal data transfer size
ComparisonComparison with internet median
1

Enter the website URL to analyze

2

The system measures page size and checks hosting via Green Web Foundation

3

CO₂ per view, annual footprint, and sustainability rating are calculated

Why measure website carbon footprint?

The internet consumes about 4% of global electricity. Every page load generates CO₂. Understanding carbon footprint is the first step toward building a greener and faster website.

CO₂ Calculation

Carbon emission estimation based on page size and data center energy consumption model.

Green Web Check

Hosting verification through The Green Web Foundation database.

Comparison

Comparison with the median website and sustainability rating.

Common Mistakes

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Ignoring page weightHeavy pages (>3 MB) are not only slow but generate significantly more CO₂.
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Not optimizing imagesImages typically account for 50-80% of page weight. WebP/AVIF can reduce size by 30-50%.
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Not using a CDNA CDN reduces data transfer distance and lowers energy consumption at the transport level.

Best Practices

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Optimize mediaUse WebP/AVIF, lazy loading, and srcset for responsive images.
✓
Choose green hostingHosting on renewable energy immediately reduces your site carbon footprint.
✓
Minify and cacheCSS/JS minification and aggressive caching reduce repeated data transfers.

What is a Website Carbon Footprint?

Every website visit consumes energy — in data centres, networks, and end-user devices. This energy produces CO₂ emissions. The carbon footprint depends on page weight, hosting energy source, and visitor volume. Lighter pages, efficient code, and green hosting providers reduce environmental impact. Grades range from A+ (cleanest) to F (heaviest footprint).

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Frequently Asked Questions

How is website carbon footprint calculated?

The volume of data transferred when loading a page is calculated and multiplied by the average CO₂ emission factor of the power grid. Factors include: page size, green hosting status, and number of views.

What affects carbon footprint?

Key factors: total page weight (HTML, CSS, JS, images, fonts), CDN usage, green hosting (renewable energy), and client-side caching.

What is "green hosting"?

Green hosting is a hosting provider that uses renewable energy sources (solar, wind) or purchases carbon offset credits. Verified through The Green Web Foundation database.

How to reduce website carbon footprint?

Optimize images (WebP/AVIF), minify CSS/JS, use a CDN, enable caching, choose green hosting, and remove unused scripts and fonts.

Related guides

Longer-form reading on this topic from the knowledge base.

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