Frequently Asked Questions: how we analyse your websites carbon footprint
How do you measure the carbon footprint of a webpage?
We use data from a variety of sources in order to determine how much Co2 is produced when someone visits your webpage. At the moment, we only analyse the specific page you run the tool against - so our scores are based on the Co2 produced by that page only.
First, we analyse the load of the webpage in order to find out how many bytes of data are downloaded for end uses. This takes into account optimisation techniques such as gzip rather than the total size of all loaded assets in order to give a real-world sum of the amount of data transfered.
Then, using data from The Green Web Foundation we measure the amount of Co2 on average it takes to transfer this amount of data.
How does the rating system work?
Our rating system is created using data from The HTTP Archive. We measure the carbon footprint of your webpage against global averages for page weight and rate the page based on which percentile it falls into.
Our bands work on the basis of which percentile your website falls into. For example, if your website's carbon footprint is lower than the top 10% of webpages, but greater than the top 5% the page would fall into band A.
| Top 5% | Top 10% | Top 20% | Top 30% | Top 40% | Top 50% | Bottom 50% | |
|---|---|---|---|---|---|---|---|
| Transfer Size (Kb) | XX | XX | XX | XX | XX | XX | XX |
| Carbon Emissions | XX | XX | XX | XX | XX | XX | XX |
| Carbon Band | A+ | A | B | C | D | E | F |
How are badges generated?
When you embed our badge script on your website, the badge served will match the rating on your generated report. If you embed the badge without first running the analysis tool, the badge will initially show a score 'pending'.
When a pending badge is returned, analysis of your website is automatically started - this usually takes a minute or two and once complete, your badge will automatically update wit the correct rating. Clicking your badge will take you to the report with full details.
How do I update my badge?
Badges are refreshed every two weeks; if your badge is over two weeks old the report will be regenerated in the background ensuring it displays the correct rating for your website.
You can also manually refresh your badge by running the analysis tool again and clicking 'Rerun' if prompted.
Why does the report say my hosting may not be run on clean energy?
Your hosting provider has not been added to the directory yet
This tool uses the Green Web Foundations' hosting directory as a reference for environmental hosting evidence. It's possible your host does run on clean energy but has not yet been added to the directory. In these cases we recommend reaching out to your hosting provider to find out more.
Your site is served on a CDN
CDNs are diffic.
Your site cannot be linked with your host
CDNs are diffic.