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https://last.fm

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
72
GRADE
C
FIX
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
D
Carbon Budget
Action
54th percentile
FIX
54th percentile
Warning::
0.75g CO2 — above the median website (0.60g)
Heavier than an estimated 46% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 54th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.75g

54th percentile

Cleaner than 46% of websites

✗ Above the median website

vs Median 24% more
vs Target 49% more
B
CO2 Per Page Load
0.75g CO2 per view
REVIEW
0.75g CO2 per view
Info::
0.75g CO2 per page view
This page transfers 3.1 MB, producing an estimated 0.75g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.15g, end-user device 0.57g.
Got: 0.75g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 89.4 kg CO2/year
With 10,000 page views per month, this page would generate approximately 89.4 kg of CO2 annually — equivalent to charging 11179 smartphones.
Info::
Green hosting reduces data center emissions

0.75g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 46% of websites

Sustainable Web Design model v4 · Page size: 3.1 MB

Your site
0.75g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.15g
End-user device
0.57g
At 10,000 monthly views: Monthly: 7.5 kg · Annual: 89.4 kg · ≈ 11179 smartphone charges
B
Green Hosting
Green (hosting)
REVIEW
Green (hosting)
Info::
Google Cloud uses renewable energy
Info::
Google Cloud: Verified by the Green Web Foundation
Info::
Google Cloud CDN: Inherits Google Cloud regional renewable mix
Info::
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 Google Cloud✓CDN Google Cloud CDN✗

Google Cloud: Verified by the Green Web Foundation

Google Cloud CDN: Inherits Google Cloud regional renewable mix

Based on known provider commitments. Verify at thegreenwebfoundation.org

C
Transfer Efficiency
Action
75% efficient
REVIEW
75% efficient
Warning::
Transfer efficiency: 75%
An estimated 820 KB (25%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 820 KB of unused JavaScript. This wasted data produces 0.19g of unnecessary CO2 per page view.
75% efficient

Total waste: 820 KB (25% of page weight)

Unused JS 820 KB

0.19g unnecessary CO2 per visit

Actual transfer 3224 KB
Theoretical minimum 2403 KB
Potential savings 820 KB (0.19g CO2)

See Deep Analysis sections above for specific optimizations.

A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 96 KB (vs 3224 KB first visit). 155 of 161 resources are served from browser cache, saving 0.72g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.75g)
First visit
3224 KB
Repeat visit
96 KB

97% reduction on repeat visits

Saving 0.72g CO2 per returning visitor

155 resources served from cache · 6 resources re-downloaded

A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Google Cloud

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

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