https://hrefs.com
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
85
GRADE
B
FIX
0
REVIEW
4
PASS
3
INFO
1
Checks
83 PASS 4 REVIEW
BCO2 Per Page Load0.54g CO2 per viewREVIEW
CO2 Per Page Load
0.54g CO2 per view
0.54g CO2 per view
Info::
0.54g CO2 per page view
This page transfers 2.3 MB, producing an estimated 0.54g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.41g.
Got: 0.54g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 64.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 64.3 kg of CO2 annually — equivalent to charging 8037 smartphones.
Info::
Green hosting reduces data center emissions
0.54g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 57% of websites
Sustainable Web Design model v4 · Page size: 2.3 MB
Your site
0.54g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.11g
End-user device
0.41g
At 10,000 monthly views: Monthly: 5.4 kg · Annual: 64.3 kg · ≈ 8037 smartphone charges
BCarbon Budget43th percentileREVIEW
Carbon Budget
43th percentile
43th percentile
Info::
0.54g CO2 — below the median website (0.60g)
Better than an estimated 57% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 43th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.54g
43rd percentile
Cleaner than 57% of websites
✗ Above the median website
vs Median 11% cleaner ✓
vs Target 7% more
BTransfer Efficiency86% efficientREVIEW
Transfer Efficiency
86% efficient
86% efficient
Info::
Transfer efficiency: 86%
An estimated 327 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 327 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
Total waste: 327 KB (14% of page weight)
Unused JS 327 KB
0.08g unnecessary CO2 per visit
Actual transfer 2318 KB
Theoretical minimum 1990 KB
Potential savings 327 KB (0.08g 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.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
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 Weight96% cachedPASS
Repeat Visit Weight
96% cached
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 83 KB (vs 2318 KB first visit). 209 of 211 resources are served from browser cache, saving 0.52g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.54g)
First visit
2318 KB
Repeat visit
83 KB
96% reduction on repeat visits
Saving 0.52g CO2 per returning visitor
209 resources served from cache · 2 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: Cloudflare
Image Optimization114 images, 165 KB total, 0 KB wastedINFO
Image Optimization
114 images, 165 KB total, 0 KB wasted
Image Optimization Audit
Total Images
114
Total Size
165 KB
15 missing alt text 110 missing dimensions 49 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.