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Sustainability

· 7 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
83
GRADE
B
FIX
1
REVIEW
1
PASS
5
INFO
0
Device:
Mobile Desktop
Checks
7
5 PASS 1 REVIEW 1 FIX
D
Transfer Efficiency
Action
59% efficient
FIX
59% efficient
Warning::
Transfer efficiency: 59%
An estimated 689 KB (41%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 689 KB of unused JavaScript. This wasted data produces 0.16g of unnecessary CO2 per page view.
59% efficient

Total waste: 689 KB (41% of page weight)

Unused JS 689 KB

0.16g unnecessary CO2 per visit

Actual transfer 1663 KB
Theoretical minimum 973 KB
Potential savings 689 KB (0.16g CO2)

See Deep Analysis sections above for specific optimizations.

B
Web Font Weight Variants
No detectable Google Fonts weights
REVIEW
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.
A
CO2 Per Page Load
0.38g CO2 per view
PASS
0.38g CO2 per view
Info::
0.38g CO2 per page view
This page transfers 1.6 MB, producing an estimated 0.38g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.08g, end-user device 0.30g.
Got: 0.38g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 46.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 46.1 kg of CO2 annually — equivalent to charging 5767 smartphones.
Info::
Green hosting reduces data center emissions

0.38g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 72% of websites

Sustainable Web Design model v4 · Page size: 1.6 MB

Your site
0.38g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.08g
End-user device
0.30g
At 10,000 monthly views: Monthly: 3.8 kg · Annual: 46.1 kg · ≈ 5767 smartphone charges
A+
Green Hosting
Green (both)
PASS
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: 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 Cloudflare✓CDN Cloudflare✓

Cloudflare: 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 Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 35 KB (vs 1663 KB first visit). 80 of 81 resources are served from browser cache, saving 0.38g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.38g)
First visit
1663 KB
Repeat visit
35 KB

98% reduction on repeat visits

Saving 0.38g CO2 per returning visitor

80 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
28th percentile
PASS
28th percentile
Info::
0.38g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 72% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 28th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.38g

28th percentile

Cleaner than 72% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 36% cleaner ✓
vs Target 23% cleaner ✓
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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