Website Carbon Footprint

Enter a domain or website URL to analyse.

Every page view moves data across the network, and moving data costs energy. This calculator loads the page, measures how many bytes a first visit actually transfers, and converts that weight into an estimate of the carbon dioxide released per visit. It is a practical way to put a number on oversized images, fonts and scripts.

What you get

Page weight of the first load, in megabytes and in raw bytes
Estimated CO2 per visit, in grams, based on the Sustainable Web Design model
A rating from A+ to D that places the page against common weight thresholds
A green hosting check against The Green Web Foundation database, with the provider name when it is known

How to read the result

Enter a domain or URL and the home page is fetched exactly as an anonymous visitor would receive it. The figure describes an uncached first visit, so returning visitors cost less; use it to compare pages rather than as an exact carbon audit. The quickest win is almost always weight: compressed images in modern formats, fewer third-party scripts, subset fonts. A green status shown as unknown only means the host is not listed in the database.

Frequently asked questions

What does the Website Carbon Footprint Checker do?

It loads your page, measures how many bytes a first visit actually transfers, and converts that page weight into an estimate of the carbon dioxide released per visit. It also checks whether the hosting provider runs on green energy.

How is the CO2 estimate calculated?

The estimate is derived from the measured transfer size using an energy model of networks and data centers, adjusted for green hosting. It is an approximation rather than an exact measurement, but it reliably shows how heavy pages compare and how changes help.

Is the carbon footprint check free?

Yes, the checker is completely free and requires no registration. Test any public page as often as you like, for instance before and after an optimization round to see the difference in weight and emissions.

How can I reduce my website's carbon footprint?

Reduce the bytes each visit transfers: compress and resize images, use modern formats, trim unused scripts and fonts, enable caching and compression. Choosing a hosting provider powered by renewable energy further lowers the emissions per visit.

What you get

Page weight of the first load, in megabytes and in raw bytes
Estimated CO2 per visit, in grams, based on the Sustainable Web Design model
A rating from A+ to D that places the page against common weight thresholds
A green hosting check against The Green Web Foundation database, with the provider name when it is known