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blurple labPAGE-WEIGHT · FREE TOOL

Every byte becomes electricity.

Weigh your page, see its CO₂ per view on the open CO2.js model, and wear the number as an embeddable badge. Lighter pages are faster, cheaper and kinder — to visitors and to the grid.

no signup · nothing stored · open methodology

WEIGH A PAGE
01we fetch your page and weigh the files it loads
02CO2.js converts bytes to grams — same model as websitecarbon
03you get a grade and a badge that keeps you honest
HOW IT WORKS

What it checks, and how to read the result.

WHAT IT CHECKS

  • It fetches the page and weighs the files its HTML loads: images, scripts, stylesheets and fonts, plus the code written into the page itself, up to 60 files.
  • It converts the total into grams of CO₂ per view with CO2.js, the open model from the Green Web Foundation, using the Sustainable Web Design method.
  • It grades the page: A under 1 MB, B under 2 MB, C under 3 MB, D above that.

HOW TO USE IT

  1. 1Enter a URL. Try your heaviest page, not only the homepage.
  2. 2Read the breakdown to see which kind of file carries the weight.
  3. 3If you like, embed the badge on your site. It weighs the page again every month, so the number stays honest.

READING THE RESULT

  • Grams per view is the estimate for one visit. The yearly figure assumes 10,000 views a month.
  • Start with the longest bar. Images are usually the biggest share, and the easiest to cut.

WHAT IT DOESN'T DO

  • Files loaded later by JavaScript, lazy-loaded images and tags added at runtime aren't counted, so the real weight is often higher.
  • It weighs files as they are served. It doesn't model caching for returning visitors or green hosting.
  • CO₂ is a model's estimate, not a meter reading. Twenty weigh-ins a day per visitor.
Find the weight you don't need: PX-RAY →
AN HONEST NOTE

The model is open. So are its limits.

We use CO2.js, the open model maintained by the Green Web Foundation — the same maths behind most carbon calculators. It estimates; it doesn't meter your data center. The number is honest enough to compare, track and improve. That's what it's for.

→The median page weighs ~2.5 MB. Ours weighs under 1.
→Images are ~half of most pages' weight — and the easiest half to fix.
→The badge re-weighs your page monthly. No gaming the number.
→Low-impact design is part of our B Corp practice: Sustainability →