LCP
Largest Contentful Paint
8.9s
Poor
Good: < 2.5s
Measures how long it takes for the main content to appear on screen
Remove Unused CSS and JavaScript
How to optimize youtube.com
Remove Unused CSS and JavaScript
High Impact+18 points estimated
Why It Matters
590KB of unused JavaScript and 176KB of unused CSS waste bandwidth and slow down parsing by over 1.7 seconds combined.
How to Fix
Use browser DevTools Coverage tab to identify unused code. Tree-shake JavaScript bundles to remove dead code. Split CSS into critical above-the-fold styles and defer non-critical styles. Consider lazy loading video player assets until user interaction.
0Needs Improvement
What This Score Means
A score of 57 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.
This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.
Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.
Core Web Vitals Analysis
INP
Interaction to Next Paint
216ms
Needs Improvement
Good: < 200ms
Measures how quickly the page responds to user interactions
CLS
Cumulative Layout Shift
0.00
Good
Good: < 0.1
Measures visual stability - how much content shifts during page load
AI Performance Analysis
YouTube's mobile site has poor performance issues with a score of 57/100. The biggest problem is multiple page redirects that waste 1.5 seconds before the page even starts loading, causing extremely slow First Contentful Paint (7.8 seconds) and Largest Contentful Paint (8.9 seconds). The site is also bloated with 590 KB of unused JavaScript and 176 KB of unused CSS that could be eliminated. Fixing the redirect chain and removing unnecessary code could dramatically improve load times and boost the performance score by 30+ points.
Other Optimization Recommendations
Eliminate Render Blocking JavaScript
High Impact+25 points estimatedWhy It Matters:
Critical JavaScript blocks initial page render for 2.3 seconds, severely delaying both FCP and LCP.
How to Fix:
Defer non-critical JavaScript by adding 'defer' or 'async' attributes to script tags. Move the 427KB main JavaScript bundle loading after critical content. Use code splitting to load only essential JavaScript for initial render, then lazy load secondary features.
Fix Multiple Page Redirects
Medium Impact+12 points estimatedWhy It Matters:
Two redirect hops add 1.5 seconds of unnecessary delay before content can start loading.
How to Fix:
Update all internal links to point directly to the mobile URL (m.youtube.com). Configure server redirects to go directly from any domain to the final mobile destination in a single hop. Remove the intermediate redirect through www.youtube.com.
Keep Your Site Fast After Optimization
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Related Performance Analyses
More Generic Speed Tests
Generic Performance Resources
Fix Layout Shift Issues
A major layout shift (CLS score of 0.492) is causing poor user experience as content jumps during page load.
Eliminate Render Blocking Resources
Critical CSS and JavaScript files are blocking page rendering for over 2 seconds, severely delaying both FCP and LCP.
Optimize Image Delivery and Sizing
Oversized images waste 124 KiB and contribute 300ms to LCP delays.
Defer Render-Blocking CSS Resources
CSS files are blocking initial render and delaying FCP/LCP by 600ms.