Shopify synthetic paint milestones and the Core Web Vitals
9.3% of audited sites (765) paint their hero element in under 300ms in the lab and pass field LCP at 98% (1.1s median), while the 23.1% exceeding 1,500ms in the lab pass field LCP at just 94% (1.4s median).
29.5% of Shopify sites use 300 to 600ms lab LCP synthetic paint milestones, and 99% of those sites have a good LCP, against 97% of all Shopify sites.
LCP pass rate
Sites with 300 to 600ms lab LCP synthetic paint milestones have a good LCP most often: 99%, against 97% of all Shopify sites. Sites with over 1,500ms lab LCP lab paint time have it least often, at 94%.
Synthetic paint milestones usage
600 to 1,500ms lab LCP is the most used: 38.2% of Shopify sites. 300 to 600ms lab LCP is 29.5% of Shopify sites.
The four LCP phases
Across the four LCP sub-parts in Chrome's field data, the largest gap between 300 to 600ms lab LCP and over 1,500ms lab LCP sits in resource load delay: 553 ms median for 300 to 600ms lab LCP against 723 ms for over 1,500ms lab LCP. Overall median field LCP is 1.2s for 300 to 600ms lab LCP (TTFB 289 ms, load delay 553 ms, load duration 148 ms, render delay 250 ms) versus 1.5s for over 1,500ms lab LCP.
Synthetic paint milestones per framework
On jQuery, 39% of sites use 600 to 1,500ms lab LCP synthetic paint milestones, and 95% of jQuery sites have a good LCP, against 97% of all sites. On Vue, 42% of sites use 600 to 1,500ms lab LCP, and 97% of Vue sites have a good LCP.
Vue 931 sites600 to 1,500ms lab LCP 42%Over 1,500ms lab LCP 27%300 to 600ms lab LCP 25%97%
jQuery 3,148 sites600 to 1,500ms lab LCP 39%Over 1,500ms lab LCP 28%300 to 600ms lab LCP 26%95%Synthetic paint milestones or the framework
Does the framework explain the synthetic paint milestones difference?
On jQuery, 99% of sites with 300 to 600ms lab LCP synthetic paint milestones have a good LCP, against 95% of jQuery sites with 600 to 1,500ms lab LCP. Within jQuery, sites with 300 to 600ms lab LCP have a good LCP more often. On Vue, 98% of sites with 300 to 600ms lab LCP synthetic paint milestones have a good LCP, against 97% of Vue sites with 600 to 1,500ms lab LCP. Within Vue, sites with 300 to 600ms lab LCP and 600 to 1,500ms lab LCP have a good LCP about equally 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 765 sites (9.3%) painting under 300ms in the lab, 98% pass field LCP (1.1s median), dropping to 94% (1.4s median) on the 23.1% (1,899) over 1,500ms.
Understanding synthetic paint milestones
Optimize unthrottled server TTFB and eliminate render-blocking head resources so the baseline paint path finishes in under 600ms in clean lab conditions. Across all audited sites, 9.3% finish lab LCP under 300ms (98% good LCP, 1.1s median) versus 23.1% above 1,500ms (94% good LCP, 1.4s median).
By Arjen Karel · 8,246 crawled Shopify sites (3,818 with desktop Chrome field data, 8,237 sites with synthetic paint milestones, October 2026). How we measured.