44.8% of React sites have no iframe count per page. Of the 55.2% that do, 47% use 1 iframe, and 84% of those sites have a good CLS, against 80% 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 99% of those sites have a good INP, against 99% 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 80% of those sites have a good LCP, against 79% of all React sites.
Core Web Vitals pass rate
Sites with 1 iframe iframe count per page have a good CLS most often: 84%, against 80% of all React sites. Sites with 4+ iframes iframe count have it least often, at 69%.
Sites with 1 iframe iframe count per page have a good INP most often: 99%, against 99% of all React sites. Sites with 2 to 3 iframes iframe count have it least often, at 98%.
Sites with 1 iframe iframe count per page have a good LCP most often: 80%, against 79% of all React sites. Sites with 2 to 3 iframes iframe count have it least often, at 73%.
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 96% of Wix sites have a good CLS, against 80% of all sites. On WordPress, 49% of sites use 0 iframes, and 75% of WordPress sites have a good CLS.
On Wix, 42% of sites use 0 iframes iframe count per page, and 100% of Wix sites have a good INP, against 99% of all sites. On WordPress, 49% of sites use 0 iframes, and 100% of WordPress sites have a good INP.
On Wix, 42% of sites use 0 iframes iframe count per page, and 92% of Wix sites have a good LCP, against 79% of all sites. On WordPress, 49% of sites use 0 iframes, and 66% of WordPress sites have a good LCP.
Wix 5,824 sites0 iframes 42%1 iframe 31%2 to 3 iframes 21%96%100%92%
WordPress 2,342 sites0 iframes 49%2 to 3 iframes 23%1 iframe 17%4+ iframes 11%75%100%66%Iframe count or the platform
Does the platform explain the iframe count per page difference?
On Wix, 96% of sites with 1 iframe iframe count per page have a good CLS, against 96% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe and 0 iframes have a good CLS about equally often. On WordPress, 77% of sites with 1 iframe iframe count per page have a good CLS, against 78% of WordPress sites with 0 iframes. Within WordPress, sites with 1 iframe and 0 iframes have a good CLS about equally often.
On Wix, 99% of sites with 1 iframe iframe count per page have a good INP, against 100% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe and 0 iframes have a good INP about equally often. On WordPress, 100% of sites with 1 iframe iframe count per page have a good INP, against 100% of WordPress sites with 0 iframes. Within WordPress, sites with 1 iframe and 0 iframes have a good INP about equally often.
On Wix, 92% of sites with 1 iframe iframe count per page have a good LCP, against 95% of Wix sites with 0 iframes. Within Wix, sites with 1 iframe and 0 iframes have a good LCP about equally often. On WordPress, 63% of sites with 1 iframe iframe count per page have a good LCP, against 73% 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, 84% pass field CLS. Adding 1 iframe (25.7%) lowers good CLS to 84%, 2 to 3 iframes (21.5%) drops good CLS to 74%, and 4 or more iframes (8.0%, 763 sites) pulls good CLS down to 69%.
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 (84% good CLS) versus 8.0% with 4+ iframes (69% good CLS).
By Arjen Karel · 9,570 crawled React sites (1,979 with desktop Chrome field data, October 2026). How we measured.