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

78% efficient

REVIEW

78% efficient

Transfer efficiency: 78%

An estimated 286 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 286 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 286 KB (22% of page weight)

Unused JS 286 KB

0.07g unnecessary CO2 per visit

Actual transfer 1277 KB

Theoretical minimum 990 KB

Potential savings 286 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

0.30g CO2 per view

PASS

0.30g CO2 per view

0.30g CO2 per page view

This page transfers 1.2 MB, producing an estimated 0.30g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.06g, end-user device 0.23g.

Got: 0.30g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 35.4 kg CO2/year

With 10,000 page views per month, this page would generate approximately 35.4 kg of CO2 annually — equivalent to charging 4427 smartphones.

Green hosting reduces data center emissions

0.30g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 81% of websites

Sustainable Web Design model v4 · Page size: 1.2 MB

Your site

0.30g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.06g

End-user device

0.23g

At 10,000 monthly views: Monthly: 3.0 kg · Annual: 35.4 kg · ≈ 4427 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 1277 KB first visit). 71 of 72 resources are served from browser cache, saving 0.29g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.30g)

First visit

1277 KB

Repeat visit

10 KB

99% reduction on repeat visits

Saving 0.29g CO2 per returning visitor

71 resources served from cache · 1 resources re-downloaded

Carbon Budget

19th percentile

PASS

19th percentile

0.30g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 81% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 19th percentile

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

Top 10%

Target

Median website

0.30g

19th percentile

Cleaner than 81% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 51% cleaner ✓

vs Target 41% 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.