At a glance the headline numbers for CMS
The CMS the site is built on, as a per-site dimension.
WordPress powers 73.3% of the sites we measured.
CMS who uses what, and how fast each group loads
Ghost sites post the best median LCP (1.1s). Wordpress sites trail at 1.9s. Correlation, not causation. computed
Passing LCP per CMS which group passes the LCP most often
96% of Shopify sites pass LCP. Wordpress trails 25 points behind, leaving 29% of its sites failing. computed
Why this matters for the Core Web Vitals, and where to start fixing it
The CMS decides your defaults: the theme's markup, the plugin economy, how images are sized, what loads in the head. Most sites never change those defaults, so the platform's choices become the platform's vitals.
No platform is doomed and none is safe. The spread inside a platform is bigger than the gap between platforms: a tuned site on a slow-median CMS beats a neglected site on a fast one. The platform pages rank them on real field data.
How does this affect the Core Web Vitals?
CMS correlates with the LCP. With Shopify, 96% of sites pass the LCP. With WordPress, 71% do. The causal link is weak: the choice mostly marks what kind of site made it.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.