Skip to content
https://ces.tech

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
60
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
D
CO2 Per Page Load
Action
0.86g CO2 per view
FIX
0.86g CO2 per view
Info::
0.86g CO2 per page view
This page transfers 3.1 MB, producing an estimated 0.86g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.16g, network 0.15g, end-user device 0.55g.
Got: 0.86g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 103.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 103.7 kg of CO2 annually — equivalent to charging 12957 smartphones.

0.86g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 43% of websites

Sustainable Web Design model v4 · Page size: 3.1 MB

Your site
0.86g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.16g
Network
0.15g
End-user device
0.55g
At 10,000 monthly views: Monthly: 8.6 kg · Annual: 103.7 kg · ≈ 12957 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::
Azure: Microsoft is carbon-negative; Azure renewable varies by region
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 Azure✗CDN Not identified✗

Azure: Microsoft is carbon-negative; Azure renewable varies by region

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
57th percentile
FIX
57th percentile
Warning::
0.86g CO2 — above the median website (0.60g)
Heavier than an estimated 43% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 57th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.86g

57th percentile

Cleaner than 43% of websites

✗ Above the median website

vs Median 44% more
vs Target 73% more
C
Transfer Efficiency
Action
66% efficient
REVIEW
66% efficient
Warning::
Transfer efficiency: 66%
An estimated 1066 KB (34%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1066 KB of unused JavaScript. This wasted data produces 0.30g of unnecessary CO2 per page view.
66% efficient

Total waste: 1066 KB (34% of page weight)

Unused JS 1066 KB

0.30g unnecessary CO2 per visit

Actual transfer 3123 KB
Theoretical minimum 2056 KB
Potential savings 1066 KB (0.30g 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
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 87 KB (vs 3123 KB first visit). 97 of 103 resources are served from browser cache, saving 0.84g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.86g)
First visit
3123 KB
Repeat visit
87 KB

97% reduction on repeat visits

Saving 0.84g CO2 per returning visitor

97 resources served from cache · 6 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