Website Carbon Calculator

Estimate how much CO₂ a web page produces per visit, check green hosting and see how it compares.

How much CO₂ does my website produce?

The calculator measures the page’s total transfer size with Google Lighthouse and applies the Sustainable Web Design model (0.81 kWh per GB, 442 g CO₂ per kWh of grid electricity, adjusted for returning visitors and green hosting). A typical 2.3 MB page emits about 0.6 g of CO₂ per visit.

Make your site lighter

Compress and resize images; serve WebP or AVIF.
Remove unused JavaScript and third-party scripts.
Cache static files and lazy-load images below the fold.
Choose green hosting powered by renewable energy.

Frequently asked questions

How accurate is it?

It is a model-based estimate; real emissions depend on networks, devices and energy mixes.

How is green hosting checked?

With The Green Web Foundation’s public database.

Is it free?

Yes.