Sustainability

· 7 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

4 PASS 3 REVIEW

Transfer Efficiency

85% efficient

REVIEW

85% efficient

Transfer efficiency: 85%

An estimated 191 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 191 KB of unused JavaScript. This wasted data produces 0.04g of unnecessary CO2 per page view.

Total waste: 191 KB (15% of page weight)

Unused JS 191 KB

0.04g unnecessary CO2 per visit

Actual transfer 1237 KB

Theoretical minimum 1046 KB

Potential savings 191 KB (0.04g 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.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

CO2 Per Page Load

0.29g CO2 per view

PASS

0.29g CO2 per view

0.29g CO2 per page view

This page transfers 1.2 MB, producing an estimated 0.29g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.06g, end-user device 0.22g.

Got: 0.29g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 34.3 kg CO2/year

With 10,000 page views per month, this page would generate approximately 34.3 kg of CO2 annually — equivalent to charging 4292 smartphones.

Green hosting reduces data center emissions

0.29g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 82% of websites

Sustainable Web Design model v4 · Page size: 1.2 MB

Your site

0.29g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.06g

End-user device

0.22g

At 10,000 monthly views: Monthly: 2.9 kg · Annual: 34.3 kg · ≈ 4292 smartphone charges

A+

Green Hosting

Green (both)

PASS

Green (both)

Both hosting and CDN use renewable energy

Got: Hosting: Vercel, CDN: Vercel

Vercel: Hosted on AWS/Google Cloud with renewable energy commitments

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 Vercel✓CDN Vercel✓

Vercel: Hosted on AWS/Google Cloud with renewable energy commitments

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+

Repeat Visit Weight

97% cached

PASS

97% cached

97% reduction on repeat visits

Returning visitors download only 38 KB (vs 1237 KB first visit). 64 of 66 resources are served from browser cache, saving 0.28g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.29g)

First visit

1237 KB

Repeat visit

38 KB

97% reduction on repeat visits

Saving 0.28g CO2 per returning visitor

64 resources served from cache · 2 resources re-downloaded

Carbon Budget

18th percentile

PASS

18th percentile

0.29g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 82% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 18th percentile

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

Top 10%

Target

Median website

0.29g

18th percentile

Cleaner than 82% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 52% cleaner ✓

vs Target 43% cleaner ✓

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