https://theguardian.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
87
GRADE
B
FIX
0
REVIEW
2
PASS
4
INFO
0
Checks
64 PASS 2 REVIEW
BTransfer Efficiency80% efficientREVIEW
Transfer Efficiency
80% efficient
80% efficient
Info::
Transfer efficiency: 80%
An estimated 237 KB (20%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 237 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
Total waste: 237 KB (20% of page weight)
Unused JS 237 KB
0.05g unnecessary CO2 per visit
Actual transfer 1207 KB
Theoretical minimum 970 KB
Potential savings 237 KB (0.05g CO2)
See Deep Analysis sections above for specific optimizations.
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
ACO2 Per Page Load0.28g CO2 per viewPASS
CO2 Per Page Load
0.28g CO2 per view
0.28g CO2 per view
Info::
0.28g CO2 per page view
This page transfers 1.2 MB, producing an estimated 0.28g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.06g, end-user device 0.21g.
Got: 0.28g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 33.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 33.5 kg of CO2 annually — equivalent to charging 4188 smartphones.
Info::
Green hosting reduces data center emissions
0.28g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 83% of websites
Sustainable Web Design model v4 · Page size: 1.2 MB
Your site
0.28g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.06g
End-user device
0.21g
At 10,000 monthly views: Monthly: 2.8 kg · Annual: 33.5 kg · ≈ 4188 smartphone charges
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Fastly: 100% renewable energy for edge network
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green Hosting✓ Green Hosted
Hosting Not identified✗CDN Fastly✓
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight88% cachedPASS
Repeat Visit Weight
88% cached
88% cached
Info::
88% reduction on repeat visits
Returning visitors download only 142 KB (vs 1207 KB first visit). 111 of 113 resources are served from browser cache, saving 0.25g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.28g)
First visit
1207 KB
Repeat visit
142 KB
88% reduction on repeat visits
Saving 0.25g CO2 per returning visitor
111 resources served from cache · 2 resources re-downloaded
ACarbon Budget17th percentilePASS
Carbon Budget
17th percentile
17th percentile
Info::
0.28g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 83% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 17th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.28g
17th percentile
Cleaner than 83% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 53% cleaner ✓
vs Target 44% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.