ShiftPress · Free carbon check
How much CO₂ does your website cost?
Enter your address. We measure your real page weight, estimate your yearly carbon footprint and show how much of the page Google finds is waste.
How we calculate this
- Model
- Sustainable Web Design Model v4
- Energy per GB
- 0.3 kWh (data centre, network and device)
- Grid intensity
- 494 g CO₂e per kWh (global average, Ember)
- Page weight
- Measured by Google PageSpeed for one mobile load of the page you enter.
- Savings
- Only what PageSpeed measures as waste on that load: unused CSS and JavaScript, oversized or old-format images, and text sent without compression. Capped at the page weight. Under 10% we call the page lean and claim no saving.
- WordPress estimate
- Shown only for WordPress sites: our average ~55% reduction after moving to a static site. It's an average, not a measurement.
- Limits
- We measure one page, not your whole site. Visits are your estimate. The per-GB energy figure is a model value researchers still debate, so read the result as a range.