https://teachable.com
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
84
GRADE
B
FIX
0
REVIEW
4
PASS
2
INFO
0
Checks
62 PASS 4 REVIEW
BCO2 Per Page Load0.52g CO2 per viewREVIEW
CO2 Per Page Load
0.52g CO2 per view
0.52g CO2 per view
Info::
0.52g CO2 per page view
This page transfers 2.2 MB, producing an estimated 0.52g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.40g.
Got: 0.52g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 61.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 61.9 kg of CO2 annually — equivalent to charging 7742 smartphones.
Info::
Green hosting reduces data center emissions
0.52g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 59% of websites
Sustainable Web Design model v4 · Page size: 2.2 MB
Your site
0.52g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.11g
End-user device
0.40g
At 10,000 monthly views: Monthly: 5.2 kg · Annual: 61.9 kg · ≈ 7742 smartphone charges
BCarbon Budget41th percentileREVIEW
Carbon Budget
41th percentile
41th percentile
Info::
0.52g CO2 — below the median website (0.60g)
Better than an estimated 59% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 41th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.52g
41st percentile
Cleaner than 59% of websites
✗ Above the median website
vs Median 14% cleaner ✓
vs Target 3% more
BTransfer Efficiency81% efficientREVIEW
Transfer Efficiency
81% efficient
81% efficient
Info::
Transfer efficiency: 81%
An estimated 428 KB (19%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 428 KB of unused JavaScript. This wasted data produces 0.10g of unnecessary CO2 per page view.
Total waste: 428 KB (19% of page weight)
Unused JS 428 KB
0.10g unnecessary CO2 per visit
Actual transfer 2233 KB
Theoretical minimum 1804 KB
Potential savings 428 KB (0.10g CO2)
See Deep Analysis sections above for specific optimizations.
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
Green (cdn)
Info::
Cloudflare CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Hosting✓ Green Hosted
Hosting Not identified✗CDN Cloudflare✓
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 39 KB (vs 2233 KB first visit). 83 of 84 resources are served from browser cache, saving 0.51g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.52g)
First visit
2233 KB
Repeat visit
39 KB
98% reduction on repeat visits
Saving 0.51g CO2 per returning visitor
83 resources served from cache · 1 resources re-downloaded
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.