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https://4.cn

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
86
GRADE
B
FIX
1
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 2 REVIEW 1 FIX
D
Green Hosting
Action
Unknown
FIX
Unknown
Info::
Hosting provider could not be identified
Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their renewable energy commitments.
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 HostingUnable to Determine
Hosting Not identified✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Transfer Efficiency
82% efficient
REVIEW
82% efficient
Info::
Transfer efficiency: 82%
An estimated 63 KB (18%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 63 KB of unused JavaScript. This wasted data produces 0.02g of unnecessary CO2 per page view.
82% efficient

Total waste: 63 KB (18% of page weight)

Unused JS 63 KB

0.02g unnecessary CO2 per visit

Actual transfer 356 KB
Theoretical minimum 293 KB
Potential savings 63 KB (0.02g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
CO2 Per Page Load
0.10g CO2 per view
PASS
0.10g CO2 per view
Info::
0.10g CO2 per page view
This page transfers 0.3 MB, producing an estimated 0.10g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.02g, end-user device 0.06g.
Got: 0.10g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 11.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 11.8 kg of CO2 annually — equivalent to charging 1480 smartphones.

0.10g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.3 MB

Your site
0.10g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.02g
End-user device
0.06g
At 10,000 monthly views: Monthly: 1.0 kg · Annual: 11.8 kg · ≈ 1480 smartphone charges
A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 11 KB (vs 356 KB first visit). 45 of 47 resources are served from browser cache, saving 0.10g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.10g)
First visit
356 KB
Repeat visit
11 KB

97% reduction on repeat visits

Saving 0.10g CO2 per returning visitor

45 resources served from cache · 2 resources re-downloaded

A+
Carbon Budget
10th percentile
PASS
10th percentile
Info::
0.10g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.10g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 84% cleaner ✓
vs Target 80% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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