Sustainability

· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Device:

Mobile Desktop

Checks

5 PASS 2 REVIEW

Transfer Efficiency

80% efficient

REVIEW

80% efficient

Transfer efficiency: 80%

An estimated 289 KB (20%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 289 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 289 KB (20% of page weight)

Unused JS 289 KB

0.07g unnecessary CO2 per visit

Actual transfer 1447 KB

Theoretical minimum 1158 KB

Potential savings 289 KB (0.07g CO2)

See Deep Analysis sections above for specific optimizations.

Web Font Weight Variants

No detectable Google Fonts weights

REVIEW

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.

CO2 Per Page Load

0.33g CO2 per view

PASS

0.33g CO2 per view

0.33g CO2 per page view

This page transfers 1.4 MB, producing an estimated 0.33g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.26g.

Got: 0.33g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 40.2 kg CO2/year

With 10,000 page views per month, this page would generate approximately 40.2 kg of CO2 annually — equivalent to charging 5020 smartphones.

Green hosting reduces data center emissions

0.33g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 77% of websites

Sustainable Web Design model v4 · Page size: 1.4 MB

Your site

0.33g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.07g

End-user device

0.26g

At 10,000 monthly views: Monthly: 3.3 kg · Annual: 40.2 kg · ≈ 5020 smartphone charges

A+

Green Hosting

Green (both)

PASS

Green (both)

Both hosting and CDN use renewable energy

Got: Hosting: GitHub Pages, CDN: Cloudflare

GitHub Pages: Verified by the Green Web Foundation

Cloudflare: 100% renewable energy for global network since 2019

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 GitHub Pages✓CDN Cloudflare✓

GitHub Pages: 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

99% cached

PASS

99% cached

99% reduction on repeat visits

Returning visitors download only 10 KB (vs 1447 KB first visit). 103 of 104 resources are served from browser cache, saving 0.33g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.33g)

First visit

1447 KB

Repeat visit

10 KB

99% reduction on repeat visits

Saving 0.33g CO2 per returning visitor

103 resources served from cache · 1 resources re-downloaded

Carbon Budget

23th percentile

PASS

23th percentile

0.33g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 77% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 23th percentile

Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.

Top 10%

Target

Median website

0.33g

23rd percentile

Cleaner than 77% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 44% cleaner ✓

vs Target 33% 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

Image Optimization

1 images, 17 KB total, 0 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

17 KB

1 missing dimensions 1 missing lazy loading

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