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Sustainable Web Design scale, from A+ to F
Eco audit · Public method
How light is your website?
Paste a page address. In under a minute: what it weighs, its footprint per visit, and what to fix first.
- Measured with Google Lighthouse
- Sustainable Web Design model
- Hosting: Green Web Foundation
- How we calculate
Try with
Internal tool · Public method
How light is your website?
For now, we use this tool for our own audits.
We will open it to everyone soon. In the meantime, we can analyse your website for you: free, no strings attached.
Ask for a free auditAnalysing
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Google really loads the page, on a phone and then on a computer: allow 20 to 60 seconds.
For comparison: the median web page weighs 2.2 MB on mobile (HTTP Archive, July 2025).
Page analysed
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The desktop measurement failed: the mobile result is still valid.
Over a year
What your page emits over a year, depending on your traffic. The rating itself covers a single visit.
How it is calculated
Calculation: Sustainable Web Design v4, as in CO2.js. The network and devices use the electricity of the chosen country (Ember averages, as used by CO2.js). Low end of the range: usage energy only, without making the hardware. High end: the former coefficient of 0.81 kWh per GB (model v3), still used by other tools. Median web page: 2.2 MB on mobile, 2.5 MB on desktop (HTTP Archive, July 2025), with the same hosting as your page.
Fix these first
The three fixes that make the page lightest.
Possible rating after these fixesEstimate based on the savings measured by Lighthouse.
What weighs
What a visitor downloads on arrival, before scrolling.
The 16 good practices
Checked automatically from the address. They refer to the French reference framework (RGESN 2024) and to the W3C guidelines.
Get the full action plan
Every fix, file by file, with the saving for each. By email, free.
Sent.
Check your inbox (and your spam folder, just in case). The link stays valid for 12 months.
Guillaume will look at your website and write to you within 2 working days.
That was our website.
You just measured shinseistudio.com: we apply to our own website what we offer our clients. Your turn: test your website, or tell us about your project.
The method
How we calculate
This is a dated estimate, not a certification or a label.
The full methodCalculation: CO2.js (Green Web Foundation, Apache-2.0 licence). Hosting: Green Web Foundation directory (ODbL licence). Comparison: HTTP Archive. Measurement: Google Lighthouse. Third parties: third-party-web (MIT licence).