Skip to content
https://jsonline.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
58
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Checks
6
1 PASS 2 REVIEW 3 FIX
F
CO2 Per Page Load
Action
1.92g CO2 per view
FIX
1.92g CO2 per view
Warning::
1.92g CO2 per page view
This page transfers 6.8 MB, producing an estimated 1.92g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.35g, network 0.33g, end-user device 1.23g.
Got: 1.92g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 229.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 229.8 kg of CO2 annually — equivalent to charging 28729 smartphones.

1.92g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 13% of websites

Sustainable Web Design model v4 · Page size: 6.8 MB

Your site
1.92g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.35g
Network
0.33g
End-user device
1.23g
At 10,000 monthly views: Monthly: 19.2 kg · Annual: 229.8 kg · ≈ 28729 smartphone charges
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

F
Carbon Budget
Action
87th percentile
FIX
87th percentile
Warning::
1.92g CO2 — above the median website (0.60g)
Heavier than an estimated 13% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 87th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.92g

87th percentile

Cleaner than 13% of websites

✗ Above the median website

vs Median 219% more
vs Target 283% more
B
Transfer Efficiency
80% efficient
REVIEW
80% efficient
Info::
Transfer efficiency: 80%
An estimated 1379 KB (20%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1379 KB of unused JavaScript. This wasted data produces 0.38g of unnecessary CO2 per page view.
80% efficient

Total waste: 1379 KB (20% of page weight)

Unused JS 1379 KB

0.38g unnecessary CO2 per visit

Actual transfer 6925 KB
Theoretical minimum 5546 KB
Potential savings 1379 KB (0.38g 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 137 KB (vs 6925 KB first visit). 657 of 689 resources are served from browser cache, saving 1.88g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 1.92g)
First visit
6925 KB
Repeat visit
137 KB

98% reduction on repeat visits

Saving 1.88g CO2 per returning visitor

657 resources served from cache · 32 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