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 2 REVIEW 1 FIX

Green Hosting

Action

Not green

FIX

Not green

No confirmed renewable energy commitment detected

Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.

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 HostingNot Green Hosted

Hosting Apache HTTP Server✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

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

A+

CO2 Per Page Load

0.15g CO2 per view

PASS

0.15g CO2 per view

0.15g CO2 per page view

This page transfers 0.5 MB, producing an estimated 0.15g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.03g, end-user device 0.10g.

Got: 0.15g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 18.3 kg CO2/year

With 10,000 page views per month, this page would generate approximately 18.3 kg of CO2 annually — equivalent to charging 2293 smartphones.

0.15g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 90% of websites

Sustainable Web Design model v4 · Page size: 0.5 MB

Your site

0.15g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.03g

Network

0.03g

End-user device

0.10g

At 10,000 monthly views: Monthly: 1.5 kg · Annual: 18.3 kg · ≈ 2293 smartphone charges

A+

Repeat Visit Weight

97% cached

PASS

97% cached

97% reduction on repeat visits

Returning visitors download only 18 KB (vs 552 KB first visit). 21 of 23 resources are served from browser cache, saving 0.15g CO2 per repeat visit.

Repeat visit: 0.01g CO2 (first visit: 0.15g)

First visit

552 KB

Repeat visit

18 KB

97% reduction on repeat visits

Saving 0.15g CO2 per returning visitor

21 resources served from cache · 2 resources re-downloaded

A+

Carbon Budget

10th percentile

PASS

10th percentile

0.15g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 10th percentile

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

Top 10%

Target

Median website

0.15g

10th percentile

Cleaner than 90% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 75% cleaner ✓

vs Target 69% cleaner ✓

A+

Transfer Efficiency

92% efficient

PASS

92% efficient

Transfer efficiency: 92%

Only 42 KB of potential savings identified. Your page is well-optimized for size.

Total waste: 42 KB (8% of page weight)

Unused JS 42 KB

0.01g unnecessary CO2 per visit

Actual transfer 552 KB

Theoretical minimum 510 KB

Potential savings 42 KB (0.01g CO2)

See Deep Analysis sections above for specific optimizations.

Image Optimization

20 images, 52 KB total, 41 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

52 KB

Oversized

Wasted

41 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.