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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
83
GRADE
B
FIX
1
REVIEW
1
PASS
5
INFO
0
Checks
75 PASS 1 REVIEW 1 FIX
DTransfer EfficiencyAction57% efficientFIX
Transfer Efficiency
Action57% efficient
57% efficient
Warning::
Transfer efficiency: 57%
An estimated 621 KB (43%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 621 KB of unused JavaScript. This wasted data produces 0.14g of unnecessary CO2 per page view.
Total waste: 621 KB (43% of page weight)
Unused JS 621 KB
0.14g unnecessary CO2 per visit
Actual transfer 1458 KB
Theoretical minimum 836 KB
Potential savings 621 KB (0.14g 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.
ACO2 Per Page Load0.34g CO2 per viewPASS
CO2 Per Page Load
0.34g CO2 per view
0.34g CO2 per view
Info::
0.34g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.34g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.26g.
Got: 0.34g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 40.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 40.5 kg of CO2 annually — equivalent to charging 5056 smartphones.
Info::
Green hosting reduces data center emissions
0.34g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 77% of websites
Sustainable Web Design model v4 · Page size: 1.4 MB
Your site
0.34g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.07g
End-user device
0.26g
At 10,000 monthly views: Monthly: 3.4 kg · Annual: 40.5 kg · ≈ 5056 smartphone charges
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: Verified by the Green Web Foundation
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Cloudflare✓CDN Cloudflare✓
Cloudflare: Verified by the Green Web Foundation
Cloudflare: 100% renewable energy for global network since 2019
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 35 KB (vs 1458 KB first visit). 62 of 63 resources are served from browser cache, saving 0.33g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.34g)
First visit
1458 KB
Repeat visit
35 KB
98% reduction on repeat visits
Saving 0.33g CO2 per returning visitor
62 resources served from cache · 1 resources re-downloaded
ACarbon Budget23th percentilePASS
Carbon Budget
23th percentile
23th percentile
Info::
0.34g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 77% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 23th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.34g
23rd percentile
Cleaner than 77% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 44% cleaner ✓
vs Target 33% cleaner ✓
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.