Skip to content
https://sfgate.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
53
GRADE
F
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
F
CO2 Per Page Load
Action
2.52g CO2 per view
FIX
2.52g CO2 per view
Critical::
2.52g CO2 per page view
This page transfers 8.9 MB, producing an estimated 2.52g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.47g, network 0.44g, end-user device 1.62g.
Got: 2.52g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 302.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 302.2 kg of CO2 annually — equivalent to charging 37775 smartphones.

2.52g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 8.9 MB

Your site
2.52g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.47g
Network
0.44g
End-user device
1.62g
At 10,000 monthly views: Monthly: 25.2 kg · Annual: 302.2 kg · ≈ 37775 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 Apache HTTP Server✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
2.52g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

2.52g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 320% more
vs Target 404% more
B
Transfer Efficiency
82% efficient
REVIEW
82% efficient
Info::
Transfer efficiency: 82%
An estimated 1633 KB (18%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1633 KB of unused JavaScript. This wasted data produces 0.45g of unnecessary CO2 per page view.
82% efficient

Total waste: 1633 KB (18% of page weight)

Unused JS 1633 KB

0.45g unnecessary CO2 per visit

Actual transfer 9106 KB
Theoretical minimum 7472 KB
Potential savings 1633 KB (0.45g 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+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 171 KB (vs 9106 KB first visit). 420 of 434 resources are served from browser cache, saving 2.47g CO2 per repeat visit.
Info::
Repeat visit: 0.05g CO2 (first visit: 2.52g)
First visit
9106 KB
Repeat visit
171 KB

98% reduction on repeat visits

Saving 2.47g CO2 per returning visitor

420 resources served from cache · 14 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback