WordPress first-party vs third-party stylesheets and the Core Web Vitals
99.9% of audited sites (63,288) serve first-party stylesheets (70% good LCP, 1.9s median), while the 59.6% (37,748) loading external third-party stylesheets drop to 68% good LCP (2.0s median).
99.9% of WordPress sites use first-party stylesheets stylesheet origin (first-party vs third-party), and 70% of those sites have a good LCP, against 70% of all WordPress sites.
LCP pass rate
Sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP most often: 70%, against 70% of all WordPress sites. Sites with third-party stylesheets CSS origin have it least often, at 68%.
Stylesheet origin (first-party vs third-party) usage
First-party stylesheets is the most used: 99.9% of WordPress sites.
LCP phase breakdown for first-party and third-party stylesheets
Across the four LCP sub-parts in Chrome's field data, the largest gap between first-party stylesheets and third-party stylesheets sits in time to first byte (TTFB): 1127 ms median for first-party stylesheets against 1162 ms for third-party stylesheets. Overall median field LCP is 1.9s for first-party stylesheets (TTFB 1127 ms, load delay 340 ms, load duration 166 ms, render delay 235 ms) versus 2.0s for third-party stylesheets.
Stylesheet origin (first-party vs third-party) per framework
Vue sets the stylesheet origin (first-party vs third-party) to first-party stylesheets on 100% of its sites, and 68% of Vue sites have a good LCP, against 70% of all sites.
Alpine 380 sitesFirst-party stylesheets 100%Third-party stylesheets 62%80%
jQuery 60,308 sitesFirst-party stylesheets 100%Third-party stylesheets 61%69%
Vue 4,844 sitesFirst-party stylesheets 100%Third-party stylesheets 35%68%
React 2,233 sitesFirst-party stylesheets 100%Third-party stylesheets 63%61%Stylesheet origin or the framework
Does the framework explain the stylesheet origin (first-party vs third-party) difference?
Almost every site with first-party stylesheets stylesheet origin (first-party vs third-party) is a jQuery site, and almost every jQuery site has first-party stylesheets stylesheet origin (first-party vs third-party), so the data can't tell first-party stylesheets stylesheet origin (first-party vs third-party) and jQuery apart. On Vue, 68% of sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP, against 65% of Vue sites with third-party stylesheets. Within Vue, sites with first-party stylesheets and third-party stylesheets have a good LCP about equally often. On React, 61% of sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP, against 56% of React sites with third-party stylesheets. Within React, sites with first-party stylesheets and third-party stylesheets have a good LCP about equally often.
How cross-origin CSS files add DNS and TLS round-trips to the critical rendering path
Because external stylesheets block rendering by default, fetching a CSS file from a third-party domain (such as fonts.googleapis.com, cdnjs, or a widget CDN) stalls first paint behind a fresh DNS lookup, TCP handshake, and TLS negotiation. Across 63,288 sites (99.9%) with first-party CSS, good LCP is 70% (1.9s median), whereas across 37,748 sites (59.6%) with third-party CSS, good LCP drops to 68% (2.0s median).
Understanding first-party vs third-party stylesheets
Self-host Google Fonts CSS and Font Awesome stylesheets on your WordPress origin so the browser does not open blocking cross-origin connections before first paint. On WordPress, 99.9% of sites serve first-party CSS (70% good LCP) while 59.6% load third-party CSS (68% good LCP, 2.0s median).
By Arjen Karel · 63,295 crawled WordPress sites (60,855 with all devices Chrome field data, 63,289 sites with stylesheet origin (first-party vs third-party), October 2026). How we measured.