https://spektrum.de
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
81
GRADE
B
FIX
0
REVIEW
4
PASS
2
INFO
0
Checks
62 PASS 4 REVIEW
BCO2 Per Page Load0.51g CO2 per viewREVIEW
CO2 Per Page Load
0.51g CO2 per view
0.51g CO2 per view
Info::
0.51g CO2 per page view
This page transfers 2.2 MB, producing an estimated 0.51g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.39g.
Got: 0.51g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 61.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 61.2 kg of CO2 annually — equivalent to charging 7647 smartphones.
Info::
Green hosting reduces data center emissions
0.51g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 60% of websites
Sustainable Web Design model v4 · Page size: 2.2 MB
Your site
0.51g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.11g
End-user device
0.39g
At 10,000 monthly views: Monthly: 5.1 kg · Annual: 61.2 kg · ≈ 7647 smartphone charges
BCarbon Budget40th percentileREVIEW
Carbon Budget
40th percentile
40th percentile
Info::
0.51g CO2 — below the median website (0.60g)
Better than an estimated 60% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 40th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.51g
40th percentile
Cleaner than 60% of websites
✗ Above the median website
vs Median 15% cleaner ✓
vs Target 2% more
BTransfer Efficiency87% efficientREVIEW
Transfer Efficiency
87% efficient
87% efficient
Info::
Transfer efficiency: 87%
An estimated 294 KB (13%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 294 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
Total waste: 294 KB (13% of page weight)
Unused JS 294 KB
0.07g unnecessary CO2 per visit
Actual transfer 2205 KB
Theoretical minimum 1910 KB
Potential savings 294 KB (0.07g 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
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 Amazon Web Services✗CDN Fastly✓
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 33 KB (vs 2205 KB first visit). 76 of 78 resources are served from browser cache, saving 0.50g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.51g)
First visit
2205 KB
Repeat visit
33 KB
98% reduction on repeat visits
Saving 0.50g CO2 per returning visitor
76 resources served from cache · 2 resources re-downloaded
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.