Website Carbon Calculator
Estimate the CO₂ produced by each page view, with a carbon rating and green hosting check.
About the Website Carbon Calculator
The internet uses a lot of electricity – for data centres, networks and the devices we browse on – and every kilobyte a page downloads adds to it. A lighter website is not only better for the planet: it also loads faster, costs visitors less mobile data and usually ranks better.
This calculator measures the weight of a page (HTML, CSS, JavaScript, images and fonts), checks whether the site is on green hosting using the Green Web Foundation database, and estimates the grams of CO₂ per page view with the Sustainable Web Design model. You get a carbon rating from A+ to F, what the page produces in a year at 10,000 views a month, everyday comparisons, the heaviest files and practical ways to reduce it.
Frequently asked questions
How accurate is the estimate?
It is a model, not a measurement. It uses average figures for energy per gigabyte and electricity carbon intensity, so treat it as a guide to compare pages and track improvements.
What is a good carbon rating?
A+ to B (under about 0.34 g per page view) is better than most of the web. Many large pages with heavy images and scripts end up at D or worse.
How do I reduce my website’s carbon footprint?
Compress and resize images, remove unused JavaScript and fonts, cache files for returning visitors, and choose a hosting provider that runs on renewable energy.