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 3 REVIEW 1 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

80% efficient

REVIEW

80% efficient

Transfer efficiency: 80%

An estimated 269 KB (20%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 269 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.

Total waste: 269 KB (20% of page weight)

Unused JS 269 KB

0.07g unnecessary CO2 per visit

Actual transfer 1316 KB

Theoretical minimum 1047 KB

Potential savings 269 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

0.36g CO2 per view

PASS

0.36g CO2 per view

0.36g CO2 per page view

This page transfers 1.3 MB, producing an estimated 0.36g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.06g, end-user device 0.23g.

Got: 0.36g CO2 Expected: < 0.50g (sustainability target)

At 10,000 monthly views: 43.7 kg CO2/year

With 10,000 page views per month, this page would generate approximately 43.7 kg of CO2 annually — equivalent to charging 5462 smartphones.

0.36g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 74% of websites

Sustainable Web Design model v4 · Page size: 1.3 MB

Your site

0.36g

Top 10%

0.20g

Target

0.50g

Median website

0.60g

Energy Breakdown

Data center

0.07g

Network

0.06g

End-user device

0.23g

At 10,000 monthly views: Monthly: 3.6 kg · Annual: 43.7 kg · ≈ 5462 smartphone charges

A+

Repeat Visit Weight

99% cached

PASS

99% cached

99% reduction on repeat visits

Returning visitors download only 8 KB (vs 1316 KB first visit). 118 of 119 resources are served from browser cache, saving 0.36g CO2 per repeat visit.

Repeat visit: 0.00g CO2 (first visit: 0.36g)

First visit

1316 KB

Repeat visit

8 KB

99% reduction on repeat visits

Saving 0.36g CO2 per returning visitor

118 resources served from cache · 1 resources re-downloaded

Carbon Budget

26th percentile

PASS

26th percentile

0.36g CO2 — below the sustainability target of 0.50g

Cleaner than an estimated 74% of websites analyzed. This page meets the Web Sustainability Guidelines target.

Estimated 26th percentile

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

Top 10%

Target

Median website

0.36g

26th percentile

Cleaner than 74% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 39% cleaner ✓

vs Target 27% cleaner ✓

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