01 · Where a page view actually goes
A web page seems weightless.
It isn't.
When someone opens your site, every byte travels from a data center, across a network, to their device. Each leg of that trip draws power. The standard estimate — the Sustainable Web Design Model, the methodology behind most website carbon tools — puts numbers on each leg:
02 · Weigh a page
Try the math yourself.
Drag the sliders. The estimate uses the same model and the global average grid (494 gCO2e per kWh). It's a proxy, not a meter — more on that below — but the direction is unambiguous: lighter pages cost less.
▲ 2.5 MB — roughly the median web page today. Plenty of small business sites ship 4–6 MB.
A modest local business site. Move it up if you run ads.
That's about 72 km driven in an average gas car — every year, just from page weight.
03 · What actually works
The fixes are boring.
That's the good news.
Typical share of page weight you can recover, by technique. Notice the same list makes a site faster, easier to use, and easier for AI search to find — one pass of careful work, three results.
04 · What we don't claim
No one can measure your website's exact emissions. Including us.
The EU's anti-greenwashing rules will soon prohibit "eco-friendly" claims without evidence. Right standard, regulation or not. So every report we produce ships with its limitations printed on it:
Carbon calculators are proxy indicators built on global averages — trend tools, not meters.
Estimates rely on published grid data and IEA/ITU constants where server-specific data isn't available.
Reports exclude embodied carbon — the footprint of manufacturing the hardware — unless noted.
What we can stand behind: "your pages are 70% lighter and your host runs on verified renewables." Numbers we measured, before and after. That's the kind of claim we make.
05 · This page, audited
We weighed this page too.
Live numbers from your browser, measured as this page loaded. No animation library, no tracker, no autoplay anything. The article practices what it preaches or it doesn't publish.
Measured with your browser's Performance API; CO2e estimated with the Sustainable Web Design Model v4 and the global average grid. Same method, same disclosures, as everything above.