44.8% of React sites have no iframe count per page. Of the 55.2% that do, 47% use 1 iframe, and 94% of those sites have a good CLS, against 92% of all React sites.
44.8% of React sites have no iframe count per page. Of the 55.2% that do, 47% use 1 iframe, and 94% of those sites have a good INP, against 92% of all React sites.
44.8% of React sites have no iframe count per page. Of the 55.2% that do, 47% use 1 iframe, and 86% of those sites have a good LCP, against 84% of all React sites.
Core Web Vitals pass rate
Sites with 1 iframe iframe count per page have a good CLS most often: 94%, against 92% of all React sites. Sites with 4+ iframes iframe count have it least often, at 84%.
Sites with 1 iframe iframe count per page have a good INP most often: 94%, against 92% of all React sites. Sites with 4+ iframes iframe count have it least often, at 85%.
Sites with 1 iframe iframe count per page have a good LCP most often: 86%, against 84% of all React sites. Sites with 4+ iframes iframe count have it least often, at 76%.
Iframe count per page usage
55.2% of React sites use iframe count per page, and 47% of those use 1 iframe.
Iframe count per page per platform
On Wix, 42% of sites use 0 iframes iframe count per page, and 97% of Wix sites have a good CLS, against 92% of all sites. On WordPress, 49% of sites use 0 iframes, and 88% of WordPress sites have a good CLS.
On Wix, 42% of sites use 0 iframes iframe count per page, and 96% of Wix sites have a good INP, against 92% of all sites. On WordPress, 49% of sites use 0 iframes, and 96% of WordPress sites have a good INP.
On Wix, 42% of sites use 0 iframes iframe count per page, and 94% of Wix sites have a good LCP, against 84% of all sites. On WordPress, 49% of sites use 0 iframes, and 63% of WordPress sites have a good LCP.
Wix 5,824 sites0 iframes 42%1 iframe 31%2 to 3 iframes 21%97%96%94%
WordPress 2,342 sites0 iframes 49%2 to 3 iframes 23%1 iframe 17%4+ iframes 11%88%96%63%Iframe count or the platform
Does the platform explain the iframe count per page difference?
On Wix, 97% of sites with 1 iframe iframe count per page have a good CLS, against 99% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe have a good CLS less often. On WordPress, 90% of sites with 1 iframe iframe count per page have a good CLS, against 90% of WordPress sites with 0 iframes. Within WordPress, sites with 1 iframe and 0 iframes have a good CLS about equally often.
On Wix, 98% of sites with 1 iframe iframe count per page have a good INP, against 98% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe and 0 iframes have a good INP about equally often. On WordPress, 96% of sites with 1 iframe iframe count per page have a good INP, against 98% of WordPress sites with 0 iframes. Within WordPress, sites with 1 iframe and 0 iframes have a good INP about equally often.
On Wix, 95% of sites with 1 iframe iframe count per page have a good LCP, against 96% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe and 0 iframes have a good LCP about equally often. On WordPress, 61% of sites with 1 iframe iframe count per page have a good LCP, against 68% of WordPress sites with 0 iframes. Within WordPress, sites with 1 iframe and 0 iframes have a good LCP about equally often.
How embedded iframes destabilize layout and multiply main-thread contexts
Every <iframe> creates an independent browsing context with its own document, styles, and scripts, and frequently resizes asynchronously after load. Across 4,287 sites (44.8%) with 0 iframes, 92% pass field CLS. Adding 1 iframe (25.7%) lowers good CLS to 94%, 2 to 3 iframes (21.5%) drops good CLS to 90%, and 4 or more iframes (8.0%, 763 sites) pulls good CLS down to 84%.
Understanding iframe count
Give every iframe container a fixed CSS aspect-ratio or min-height so async frame initialization cannot shift surrounding content, add loading="lazy" to below-the-fold embeds, and replace heavy video players with static preview facades. Across all audited sites, 44.8% use 0 iframes (92% good CLS) versus 8.0% with 4+ iframes (84% good CLS).
By Arjen Karel · 9,570 crawled React sites (5,488 with phone Chrome field data, October 2026). How we measured.