The short answer
Core Web Vitals measure real-user loading (LCP), responsiveness (INP) and visual stability (CLS). Custom-coded sites tend to pass more easily because they ship less code. WordPress sites can pass with a light theme, good hosting and few plugins. Page experience is one of many ranking signals, so speed helps most when your content is already competitive.
- Check real-user data in Search Console, not only lab tests.
- Interaction to Next Paint replaced First Input Delay in 2024.
- JavaScript weight is the most common cause of poor INP.
- Speed supports rankings; it does not replace good content.
Custom code vs WordPress at a glance
| What matters | Custom code | WordPress |
|---|---|---|
| LCP | Pre-rendered HTML and optimised images | Needs caching and image plugins |
| INP | Little JavaScript by default | Builder and plugin scripts add up |
| CLS | Controlled layouts and font loading | Theme and ad dependent |
Where to find your numbers
Search Console’s Core Web Vitals report groups your URLs by status using real Chrome user data. PageSpeed Insights shows the same field data per URL. Sources: Core Web Vitals on web.dev, PageSpeed Insights
Platform-level patterns
The HTTP Archive Web Almanac publishes Core Web Vitals pass rates by CMS and framework. Use it to see how platforms compare at scale, then measure your own site. Sources: HTTP Archive Web Almanac, CMS chapter
Quick wins on WordPress
Use a block theme instead of a heavy builder, add full-page caching, serve modern image formats and remove unused plugins.
Our verdict
If you are rebuilding anyway and search matters, custom code gives the best starting point for Core Web Vitals.
Questions people ask
Do Core Web Vitals affect rankings?
They are part of Google’s page experience signals. Relevance and quality matter more.
What is a good LCP?
Under 2.5 seconds for at least 75 percent of page loads.
What is INP?
Interaction to Next Paint, which measures how quickly a page responds to taps and clicks.
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