Website Carbon Calculator
Calculate the carbon footprint of any web page. See CO2 per visit, annual emissions, page weight breakdown, and tips to reduce your impact.
The Internet's Carbon Footprint
4% of Global Emissions
The internet produces roughly the same carbon emissions as the airline industry. Every page load consumes energy across data centers, networks, and devices.
2.5 MB Average Page
The average web page in 2026 weighs 2.5 MB — 3x larger than in 2015. Bloated JavaScript, unoptimized images, and third-party scripts are the main culprits.
ESG & Sustainability
Companies are increasingly reporting on digital sustainability. A lighter, faster website reduces energy consumption and demonstrates environmental responsibility.
Performance = Green
The same optimizations that improve page speed (compression, caching, lazy loading) also reduce carbon emissions. Fast websites are green websites.
How We Calculate Carbon
- 1. Page weight — We fetch the page and estimate total transfer size (HTML, images, scripts, CSS, video)
- 2. Energy per byte — Using industry-standard factors: ~0.81 kWh per GB transferred (data center + network + end device)
- 3. CO₂ per kWh — Global average grid intensity: ~0.442 kg CO₂ per kWh
- 4. Annual projection — Multiplied by estimated monthly page views (10,000 default)
Methodology based on The Green Web Foundation, HTTP Archive data, and IEA grid emission factors. Estimates are approximate — actual emissions depend on hosting provider, green energy usage, caching, and real traffic.
Frequently Asked Questions
How accurate is this carbon calculator?
This provides an estimate based on page weight and industry-standard emission factors. Actual emissions depend on your hosting provider (green vs fossil), CDN usage, caching, and real traffic volume. Use this as a benchmark, not an exact measurement.
What's a good carbon grade for a website?
An A or A+ grade means your page is under 1 MB and among the cleanest 85%+ of websites. B is good, C is average, and D/F indicate significant optimization opportunities. Most sites can improve by compressing images and removing unused JavaScript.
How do I reduce my website's carbon footprint?
The biggest impact comes from: 1) Optimizing images (use WebP/AVIF, lazy loading), 2) Removing unused JavaScript, 3) Enabling compression (Brotli/Gzip), 4) Using a green hosting provider, 5) Implementing caching. These same changes also improve page speed.
Does sustainable web design affect SEO?
Indirectly, yes. The optimizations that reduce carbon (lighter pages, faster load times, efficient code) are the same ones Google rewards with better Core Web Vitals scores and higher rankings. Sustainable web design and SEO are aligned.