https://katebarton.co.uk
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
75
GRADE
C
FIX
2
REVIEW
3
PASS
2
INFO
1
Checks
82 PASS 3 REVIEW 2 FIX
DCO2 Per Page LoadAction1.23g CO2 per viewFIX
CO2 Per Page Load
Action1.23g CO2 per view
1.23g CO2 per view
Warning::
1.23g CO2 per page view
This page transfers 5.2 MB, producing an estimated 1.23g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.26g, end-user device 0.95g.
Got: 1.23g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 148.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 148.2 kg of CO2 annually — equivalent to charging 18519 smartphones.
Info::
Green hosting reduces data center emissions
1.23g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 32% of websites
Sustainable Web Design model v4 · Page size: 5.2 MB
Your site
1.23g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.03g
Network
0.26g
End-user device
0.95g
At 10,000 monthly views: Monthly: 12.3 kg · Annual: 148.2 kg · ≈ 18519 smartphone charges
DCarbon BudgetAction68th percentileFIX
Carbon Budget
Action68th percentile
68th percentile
Warning::
1.23g CO2 — above the median website (0.60g)
Heavier than an estimated 32% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 68th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.23g
68th percentile
Cleaner than 32% of websites
✗ Above the median website
vs Median 106% more
vs Target 147% more
BTransfer Efficiency89% efficientREVIEW
Transfer Efficiency
89% efficient
89% efficient
Info::
Transfer efficiency: 89%
An estimated 576 KB (11%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 576 KB of unused JavaScript. This wasted data produces 0.13g of unnecessary CO2 per page view.
Total waste: 576 KB (11% of page weight)
Unused JS 576 KB
0.13g unnecessary CO2 per visit
Actual transfer 5341 KB
Theoretical minimum 4764 KB
Potential savings 576 KB (0.13g CO2)
See Deep Analysis sections above for specific optimizations.
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
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 GoDaddy✗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 121 KB (vs 5341 KB first visit). 531 of 539 resources are served from browser cache, saving 1.21g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 1.23g)
First visit
5341 KB
Repeat visit
121 KB
98% reduction on repeat visits
Saving 1.21g CO2 per returning visitor
531 resources served from cache · 8 resources re-downloaded
Image Optimization146 images, 330 KB total, 0 KB wastedINFO
Image Optimization
146 images, 330 KB total, 0 KB wasted
Image Optimization Audit
Total Images
146
Total Size
330 KB
6 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.