Performance Website Audit
A performance audit measures how quickly your website loads and responds. This includes initial load times, interaction responsiveness, visual stability, and the technical factors that affect user experience and search rankings.
Page speed directly affects bounce rates, conversion rates, and search rankings. A site that loads in 1 second has a conversion rate 2.5x higher than one that loads in 5 seconds. Google measures performance and uses it as a ranking signal.
What a performance audit examines
Core Web Vitals
LCP, INP, and CLS - the metrics Google uses to evaluate page experience.
Common issues
- Largest Contentful Paint above 2.5s
- Interaction to Next Paint above 200ms
- Cumulative Layout Shift above 0.1
- Poor mobile performance scores
Loading behaviour
How content appears during load - what users see and when they can interact.
Common issues
- Render-blocking resources
- Flash of unstyled content
- Long white screen periods
- JavaScript blocking interaction
Image optimisation
Format selection, compression, responsive sizing, and lazy loading strategies.
Common issues
- Uncompressed images
- Wrong formats for content type
- Missing width/height attributes
- Images loading off-screen
Code efficiency
JavaScript bundle sizes, CSS delivery, and third-party script impact.
Common issues
- Excessive JavaScript
- Unused CSS rules
- Third-party bloat
- No code splitting
Server configuration
Response times, caching policies, compression, and CDN implementation.
Common issues
- No browser caching
- Missing compression
- Slow server response
- No CDN for static assets
Mobile performance
How the site performs on mobile networks and less powerful devices.
Common issues
- Heavy pages on 3G/4G
- CPU-intensive scripts
- Touch responsiveness
- Viewport configuration
Common performance problems
Unoptimised hero images
The largest element on the page is often an uncompressed, oversized hero image. This directly impacts LCP.
Impact: LCP fails, affecting both user experience and search rankings.
Third-party script bloat
Analytics, chat widgets, marketing pixels, and social embeds accumulate. Each adds network requests and JavaScript execution time.
Impact: Pages become slow despite optimised first-party code.
No lazy loading
Images and embeds below the fold load immediately, competing with critical content for bandwidth.
Impact: Initial load is slower than necessary.
Missing caching headers
Browsers re-download resources that should be cached, wasting bandwidth on repeat visits.
Impact: Return visitors experience unnecessary slowness.
Part of the wider Commercial Assessment
A performance audit tells you what is slow. It does not tell you whether the performance issues are causing the commercial problems you are experiencing.
- Performance problems often have organisational causes: no performance budget, no monitoring, developers adding features without considering load impact.
- Fixing performance without fixing the development process means new performance problems will emerge with every release.
- Some performance investments are not worth making: the commercial impact may not justify the engineering cost.
The Commercial Assessment examines performance alongside five other domains: channels and reporting, attribution, sales handoff, user experience, and team capability. Page speed is one factor in a larger system.
Learn about Commercial AssessmentSpeed is money
If your site is slow, that costs you visitors and conversions. But if you suspect the problem is systemic, not just performance, you need a broader assessment.