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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
68
GRADE
D
FIX
3
REVIEW
3
PASS
1
INFO
1
Device:
Mobile Desktop
Checks
8
1 PASS 3 REVIEW 3 FIX
D
CO2 Per Page Load
Action
1.24g CO2 per view
FIX
1.24g CO2 per view
Warning::
1.24g CO2 per page view
This page transfers 4.4 MB, producing an estimated 1.24g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.23g, network 0.21g, end-user device 0.80g.
Got: 1.24g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 149.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 149.0 kg of CO2 annually — equivalent to charging 18630 smartphones.

1.24g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 32% of websites

Sustainable Web Design model v4 · Page size: 4.4 MB

Your site
1.24g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.23g
Network
0.21g
End-user device
0.80g
At 10,000 monthly views: Monthly: 12.4 kg · Annual: 149.0 kg · ≈ 18630 smartphone charges
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
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 HostingNot Green Hosted
Hosting Amazon Web Services✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
68th percentile
FIX
68th percentile
Warning::
1.24g CO2 — above the median website (0.60g)
Heavier than an estimated 32% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 68th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.24g

68th percentile

Cleaner than 32% of websites

✗ Above the median website

vs Median 107% more
vs Target 148% more
B
Transfer Efficiency
78% efficient
REVIEW
78% efficient
Info::
Transfer efficiency: 78%
An estimated 998 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 998 KB of unused JavaScript. This wasted data produces 0.28g of unnecessary CO2 per page view.
78% efficient

Total waste: 998 KB (22% of page weight)

Unused JS 998 KB

0.28g unnecessary CO2 per visit

Actual transfer 4490 KB
Theoretical minimum 3491 KB
Potential savings 998 KB (0.28g 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+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 95 KB (vs 4490 KB first visit). 125 of 126 resources are served from browser cache, saving 1.22g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 1.24g)
First visit
4490 KB
Repeat visit
95 KB

98% reduction on repeat visits

Saving 1.22g CO2 per returning visitor

125 resources served from cache · 1 resources re-downloaded

Image Optimization
22 images, 294 KB total, 9 KB wasted
INFO

Image Optimization Audit

Total Images

22

Total Size

294 KB

Oversized

2

Wasted

9 KB

9 missing dimensions 9 missing lazy loading
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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