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Sustainability
· 7 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
3
INFO
0
Checks
73 PASS 4 REVIEW
BCO2 Per Page Load0.58g CO2 per viewREVIEW
CO2 Per Page Load
0.58g CO2 per view
0.58g CO2 per view
Info::
0.58g CO2 per page view
This page transfers 2.5 MB, producing an estimated 0.58g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.12g, end-user device 0.45g.
Got: 0.58g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 70.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 70.0 kg of CO2 annually — equivalent to charging 8744 smartphones.
Info::
Green hosting reduces data center emissions
0.58g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 52% of websites
Sustainable Web Design model v4 · Page size: 2.5 MB
Your site
0.58g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.12g
End-user device
0.45g
At 10,000 monthly views: Monthly: 5.8 kg · Annual: 70.0 kg · ≈ 8744 smartphone charges
BCarbon Budget48th percentileREVIEW
Carbon Budget
48th percentile
48th percentile
Info::
0.58g CO2 — below the median website (0.60g)
Better than an estimated 52% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 48th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.58g
48th percentile
Cleaner than 52% of websites
✗ Above the median website
vs Median 3% cleaner ✓
vs Target 17% more
CTransfer EfficiencyAction67% efficientREVIEW
Transfer Efficiency
Action67% efficient
67% efficient
Warning::
Transfer efficiency: 67%
An estimated 828 KB (33%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 828 KB of unused JavaScript. This wasted data produces 0.19g of unnecessary CO2 per page view.
Total waste: 828 KB (33% of page weight)
Unused JS 828 KB
0.19g unnecessary CO2 per visit
Actual transfer 2522 KB
Theoretical minimum 1693 KB
Potential savings 828 KB (0.19g CO2)
See Deep Analysis sections above for specific optimizations.
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Amazon Web Services, CDN: Fastly
Info::
Amazon Web Services: Verified by the Green Web Foundation
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✓
Amazon Web Services: Verified by the Green Web Foundation
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight97% cachedPASS
Repeat Visit Weight
97% cached
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 69 KB (vs 2522 KB first visit). 92 of 93 resources are served from browser cache, saving 0.57g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.58g)
First visit
2522 KB
Repeat visit
69 KB
97% reduction on repeat visits
Saving 0.57g CO2 per returning visitor
92 resources served from cache · 1 resources re-downloaded
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.