WordPress synthetic paint milestones and the Core Web Vitals
16.1% of audited sites (10,190) paint their hero element in under 300ms in the lab and pass field LCP at 89% (1.4s median), while the 32.4% exceeding 1,500ms in the lab pass field LCP at just 48% (2.6s median).
16.1% of WordPress sites use under 300ms lab LCP synthetic paint milestones, and 89% of those sites have a good LCP, against 70% of all WordPress sites.
LCP pass rate
Sites with under 300ms lab LCP synthetic paint milestones have a good LCP most often: 89%, against 70% of all WordPress sites. Sites with over 1,500ms lab LCP lab paint time have it least often, at 48%.
Synthetic paint milestones usage
Over 1,500ms lab LCP is the most used: 32.4% of WordPress sites. Under 300ms lab LCP is 16.1% of WordPress sites.
The four LCP phases
Across the four LCP sub-parts in Chrome's field data, the largest gap between under 300ms lab LCP and over 1,500ms lab LCP sits in time to first byte (TTFB): 680 ms median for under 300ms lab LCP against 1590 ms for over 1,500ms lab LCP. Overall median field LCP is 1.4s for under 300ms lab LCP (TTFB 680 ms, load delay 260 ms, load duration 168 ms, render delay 230 ms) versus 2.6s for over 1,500ms lab LCP.
Synthetic paint milestones per framework
On jQuery, 33% of sites use over 1,500ms lab LCP synthetic paint milestones, and 69% of jQuery sites have a good LCP, against 70% of all sites. On Vue, 44% of sites use over 1,500ms lab LCP, and 67% of Vue sites have a good LCP.
Alpine 377 sites600 to 1,500ms lab LCP 27%Over 1,500ms lab LCP 26%Under 300ms lab LCP 24%300 to 600ms lab LCP 23%78%
jQuery 60,182 sitesOver 1,500ms lab LCP 33%600 to 1,500ms lab LCP 31%300 to 600ms lab LCP 21%Under 300ms lab LCP 15%69%
Vue 4,841 sitesOver 1,500ms lab LCP 44%600 to 1,500ms lab LCP 26%300 to 600ms lab LCP 18%Under 300ms lab LCP 12%67%
React 2,227 sitesOver 1,500ms lab LCP 40%600 to 1,500ms lab LCP 29%300 to 600ms lab LCP 19%Under 300ms lab LCP 12%63%Synthetic paint milestones or the framework
Does the framework explain the synthetic paint milestones difference?
On jQuery, 88% of sites with under 300ms lab LCP synthetic paint milestones have a good LCP, against 48% of jQuery sites with over 1,500ms lab LCP. Within jQuery, sites with under 300ms lab LCP have a good LCP more often. On Vue, 88% of sites with under 300ms lab LCP synthetic paint milestones have a good LCP, against 53% of Vue sites with over 1,500ms lab LCP. Within Vue, sites with under 300ms lab LCP have a good LCP more often.
How clean lab paint timings translate to real-user field LCP
Synthetic paint milestones measure your page without real-user cellular latency or cold device caches. A page that already takes over 1.5 seconds in a fast lab environment rarely survives real-world mobile networks. Across 10,190 sites (16.1%) painting under 300ms in the lab, 89% pass field LCP (1.4s median), dropping to 48% (2.6s median) on the 32.4% (20,465) over 1,500ms.
Understanding synthetic paint milestones
Serve cached full-page HTML and remove render-blocking head scripts so unthrottled lab LCP finishes under 600ms. On WordPress, 16.1% of sites paint under 300ms in the lab (89% good field LCP) while 32.4% exceed 1,500ms (48% good field LCP).
By Arjen Karel · 63,295 crawled WordPress sites (36,524 with phone Chrome field data, 63,151 sites with synthetic paint milestones, October 2026). How we measured.