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

4 PASS 3 REVIEW

Transfer Efficiency

Action

70% efficient

REVIEW

70% efficient

Transfer efficiency: 70%

An estimated 292 KB (30%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 292 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 292 KB (30% of page weight)

Unused JS 292 KB

0.07g unnecessary CO2 per visit

Actual transfer 974 KB

Theoretical minimum 681 KB

Potential savings 292 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.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

CO2 Per Page Load

0.23g CO2 per view

PASS

0.23g CO2 per view

0.23g CO2 per page view

This page transfers 1.0 MB, producing an estimated 0.23g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.05g, end-user device 0.17g.

Got: 0.23g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 27.0 kg CO2/year

With 10,000 page views per month, this page would generate approximately 27.0 kg of CO2 annually — equivalent to charging 3377 smartphones.

Green hosting reduces data center emissions

0.23g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 88% of websites

Sustainable Web Design model v4 · Page size: 1.0 MB

Your site

0.23g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.01g

Network

0.05g

End-user device

0.17g

At 10,000 monthly views: Monthly: 2.3 kg · Annual: 27.0 kg · ≈ 3377 smartphone charges

Green Hosting

Green (cdn)

PASS

Green (cdn)

Netlify CDN uses renewable energy

Since most traffic is served through the CDN, the majority of data transfer energy is renewable.

Netlify: Hosted on AWS/Google Cloud with renewable energy matching

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 Not identified✗CDN Netlify✓

Netlify: Hosted on AWS/Google Cloud with renewable energy matching

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 30 KB (vs 974 KB first visit). 68 of 73 resources are served from browser cache, saving 0.22g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.23g)

First visit

974 KB

Repeat visit

30 KB

97% reduction on repeat visits

Saving 0.22g CO2 per returning visitor

68 resources served from cache · 5 resources re-downloaded

Carbon Budget

12th percentile

PASS

12th percentile

0.23g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 88% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 12th percentile

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

Top 10%

Target

Median website

0.23g

12th percentile

Cleaner than 88% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 62% cleaner ✓

vs Target 55% cleaner ✓

Image Optimization

5 images, 298 KB total, 148 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

298 KB

Oversized

Wasted

148 KB

5 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.