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

3 PASS 2 REVIEW 2 FIX

Green Hosting

Action

Unknown

FIX

Unknown

Hosting provider could not be identified

Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their 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 HostingUnable to Determine

Hosting Not identified✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

Transfer Efficiency

Action

57% efficient

FIX

57% efficient

Transfer efficiency: 57%

An estimated 398 KB (43%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 398 KB of unused JavaScript. This wasted data produces 0.11g of unnecessary CO2 per page view.

Total waste: 398 KB (43% of page weight)

Unused JS 398 KB

0.11g unnecessary CO2 per visit

Actual transfer 923 KB

Theoretical minimum 524 KB

Potential savings 398 KB (0.11g 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

0.26g CO2 per view

PASS

0.26g CO2 per view

0.26g CO2 per page view

This page transfers 0.9 MB, producing an estimated 0.26g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.05g, network 0.04g, end-user device 0.16g.

Got: 0.26g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 30.6 kg CO2/year

With 10,000 page views per month, this page would generate approximately 30.6 kg of CO2 annually — equivalent to charging 3829 smartphones.

0.26g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 85% of websites

Sustainable Web Design model v4 · Page size: 0.9 MB

Your site

0.26g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.05g

Network

0.04g

End-user device

0.16g

At 10,000 monthly views: Monthly: 2.6 kg · Annual: 30.6 kg · ≈ 3829 smartphone charges

A+

Repeat Visit Weight

100% cached

PASS

100% cached

100% reduction on repeat visits

Returning visitors download only 3 KB (vs 923 KB first visit). 36 of 37 resources are served from browser cache, saving 0.25g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.26g)

First visit

923 KB

Repeat visit

3 KB

100% reduction on repeat visits

Saving 0.25g CO2 per returning visitor

36 resources served from cache · 1 resources re-downloaded

Carbon Budget

15th percentile

PASS

15th percentile

0.26g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 85% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 15th percentile

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

Top 10%

Target

Median website

0.26g

15th percentile

Cleaner than 85% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 57% cleaner ✓

vs Target 49% cleaner ✓

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