https://improvingliteracy.org
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
81
GRADE
B
FIX
1
REVIEW
2
PASS
4
INFO
1
Checks
84 PASS 2 REVIEW 1 FIX
DTransfer EfficiencyAction58% efficientFIX
Transfer Efficiency
Action58% efficient
58% efficient
Warning::
Transfer efficiency: 58%
An estimated 885 KB (42%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 885 KB of unused JavaScript. This wasted data produces 0.20g of unnecessary CO2 per page view.
Total waste: 885 KB (42% of page weight)
Unused JS 885 KB
0.20g unnecessary CO2 per visit
Actual transfer 2122 KB
Theoretical minimum 1236 KB
Potential savings 885 KB (0.20g CO2)
See Deep Analysis sections above for specific optimizations.
BCarbon Budget39th percentileREVIEW
Carbon Budget
39th percentile
39th percentile
Info::
0.49g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 61% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 39th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.49g
39th percentile
Cleaner than 61% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 18% cleaner ✓
vs Target 2% cleaner ✓
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.
ACO2 Per Page Load0.49g CO2 per viewPASS
CO2 Per Page Load
0.49g CO2 per view
0.49g CO2 per view
Info::
0.49g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.49g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.10g, end-user device 0.38g.
Got: 0.49g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 58.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 58.9 kg of CO2 annually — equivalent to charging 7359 smartphones.
Info::
Green hosting reduces data center emissions
0.49g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 61% of websites
Sustainable Web Design model v4 · Page size: 2.1 MB
Your site
0.49g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.10g
End-user device
0.38g
At 10,000 monthly views: Monthly: 4.9 kg · Annual: 58.9 kg · ≈ 7359 smartphone charges
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Kinsta, CDN: Cloudflare
Info::
Kinsta: Verified by the Green Web Foundation
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 Kinsta✓CDN Cloudflare✓
Kinsta: Verified by the Green Web Foundation
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight97% cachedPASS
Repeat Visit Weight
97% cached
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 59 KB (vs 2122 KB first visit). 62 of 65 resources are served from browser cache, saving 0.48g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.49g)
First visit
2122 KB
Repeat visit
59 KB
97% reduction on repeat visits
Saving 0.48g CO2 per returning visitor
62 resources served from cache · 3 resources re-downloaded
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Something Familiar
Image Optimization16 images, 222 KB total, 1 KB wastedINFO
Image Optimization
16 images, 222 KB total, 1 KB wasted
Image Optimization Audit
Total Images
16
Total Size
222 KB
Oversized
1
Wasted
1 KB
12 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.