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Sustainability

· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
73
GRADE
C
FIX
2
REVIEW
2
PASS
3
INFO
1
Device:
Mobile Desktop
Checks
8
3 PASS 2 REVIEW 2 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

D
Transfer Efficiency
Action
55% efficient
FIX
55% efficient
Warning::
Transfer efficiency: 55%
An estimated 622 KB (45%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 622 KB of unused JavaScript. This wasted data produces 0.17g of unnecessary CO2 per page view.
55% efficient

Total waste: 622 KB (45% of page weight)

Unused JS 622 KB

0.17g unnecessary CO2 per visit

Actual transfer 1388 KB
Theoretical minimum 766 KB
Potential savings 622 KB (0.17g CO2)

See Deep Analysis sections above for specific optimizations.

B
Web Font Weight Variants
No detectable Google Fonts weights
REVIEW
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.
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
0.38g CO2 per view
PASS
0.38g CO2 per view
Info::
0.38g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.38g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.07g, end-user device 0.25g.
Got: 0.38g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 46.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 46.1 kg of CO2 annually — equivalent to charging 5759 smartphones.

0.38g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 72% of websites

Sustainable Web Design model v4 · Page size: 1.4 MB

Your site
0.38g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.07g
Network
0.07g
End-user device
0.25g
At 10,000 monthly views: Monthly: 3.8 kg · Annual: 46.1 kg · ≈ 5759 smartphone charges
A+
Repeat Visit Weight
96% cached
PASS
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 48 KB (vs 1388 KB first visit). 75 of 77 resources are served from browser cache, saving 0.37g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.38g)
First visit
1388 KB
Repeat visit
48 KB

96% reduction on repeat visits

Saving 0.37g CO2 per returning visitor

75 resources served from cache · 2 resources re-downloaded

A
Carbon Budget
28th percentile
PASS
28th percentile
Info::
0.38g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 72% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 28th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.38g

28th percentile

Cleaner than 72% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 36% cleaner ✓
vs Target 23% cleaner ✓
Image Optimization
1 images, 0 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

1

Total Size

0 KB

1 missing alt text 1 missing dimensions
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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