How much carbon does a web page cost?

Enter the address of a page. We load it once in a real browser and weigh everything it downloads. Then we estimate the carbon each visit causes, with a published method.

Check a web page

Results are public: anyone with the link to a result can see it. Don’t check private pages, or links that carry a password or a token.

How the checker works

CO2 in the air

426.07 ppm

The average for September 2026, measured at Mauna Loa in Hawaii.

ppm (parts per million) is how many of every million molecules of dry air are carbon dioxide. The line is every monthly average since March 1958, when it was 315.71 ppm.

Source: NOAA, as of 16 October 2026.

See the full record

More to read

  • The Kettle Question

    Does an AI prompt boil a kettle? The published figures for the energy and carbon of everyday digital life.

  • Is your web host green?

    Hosts ranked greenest first, with what each one costs, who it suits and how green it is.

  • CO2 since you were born

    Compare the carbon dioxide in the air in the year you were born with the latest full year.

Back to top