Skip to content
https://kff.org

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
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
F
CO2 Per Page Load
Action
1.67g CO2 per view
FIX
1.67g CO2 per view
Warning::
1.67g CO2 per page view
This page transfers 5.9 MB, producing an estimated 1.67g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.31g, network 0.29g, end-user device 1.07g.
Got: 1.67g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 200.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 200.2 kg of CO2 annually — equivalent to charging 25020 smartphones.

1.67g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 20% of websites

Sustainable Web Design model v4 · Page size: 5.9 MB

Your site
1.67g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.31g
Network
0.29g
End-user device
1.07g
At 10,000 monthly views: Monthly: 16.7 kg · Annual: 200.2 kg · ≈ 25020 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
80th percentile
FIX
80th percentile
Warning::
1.67g CO2 — above the median website (0.60g)
Heavier than an estimated 20% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 80th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.67g

80th percentile

Cleaner than 20% of websites

✗ Above the median website

vs Median 178% more
vs Target 234% more
B
Transfer Efficiency
78% efficient
REVIEW
78% efficient
Info::
Transfer efficiency: 78%
An estimated 1334 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1334 KB of unused JavaScript. This wasted data produces 0.37g of unnecessary CO2 per page view.
78% efficient

Total waste: 1334 KB (22% of page weight)

Unused JS 1334 KB

0.37g unnecessary CO2 per visit

Actual transfer 6031 KB
Theoretical minimum 4696 KB
Potential savings 1334 KB (0.37g 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
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 86 KB (vs 6031 KB first visit). 123 of 127 resources are served from browser cache, saving 1.64g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 1.67g)
First visit
6031 KB
Repeat visit
86 KB

99% reduction on repeat visits

Saving 1.64g CO2 per returning visitor

123 resources served from cache · 4 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