57.0% of sites have no iframe count per page. Of the 43.0% that do, 40% use 1 iframe, and 77% of those sites have a good CLS, against 78% of all sites.
57.0% of sites have no iframe count per page. Of the 43.0% that do, 40% use 1 iframe, and 99% of those sites have a good INP, against 99% of all sites.
57.0% of sites have no iframe count per page. Of the 43.0% that do, 40% use 1 iframe, and 86% of those sites have a good LCP, against 86% of all sites.
Core Web Vitals pass rate
Sites with 1 iframe iframe count per page have a good CLS most often: 77%, against 78% of all sites. Sites with 4+ iframes iframe count have it least often, at 73%.
Sites with 1 iframe iframe count per page have a good INP most often: 99%, against 99% of all sites. Sites with 4+ iframes iframe count have it least often, at 98%.
Sites with 1 iframe iframe count per page have a good LCP most often: 86%, against 86% of all sites. Sites with 4+ iframes iframe count have it least often, at 84%.
Iframe count per page usage
43.0% of sites use iframe count per page, and two in five of those use 1 iframe.
Understanding iframe count
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 115,754 sites (57.0%) with 0 iframes, 80% pass field CLS. Adding 1 iframe (17.3%) lowers good CLS to 77%, 2 to 3 iframes (17.3%) drops good CLS to 77%, and 4 or more iframes (8.3%, 16,883 sites) pulls good CLS down to 73%.
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, 57.0% use 0 iframes (80% good CLS) versus 8.3% with 4+ iframes (73% good CLS).
How iframe count per page plays out per platform
What the field data shows when you isolate a single CMS or framework.
WordPress 65,939 sites WordPress pages embedding 4+ iframes (9.1%) pass field CLS at 73% vs 80% with 0 iframes.
Across 65,939 WordPress sites, 53.6% embed 0 iframes (80% good CLS), 16.2% embed 1 iframe (76%), 21.2% embed 2 to 3 (77%), and 9.1% embed 4+ iframes (73% good CLS).
Shopify 8,634 stores 79% of Shopify stores embed iframes, with 4+ iframe stores (17.9%) passing CLS at 81%.
Across Shopify storefronts, 21.4% have 0 iframes (89% good CLS), 32.4% have 1 iframe (89%), 28.3% have 2 to 3 (86%), and 17.9% have 4+ iframes (81% good CLS).
React & Next.js 9,658 sites React & Next.js sites with 4+ iframes (8.0%) pass field CLS at 70% vs 84% with 0 iframes.
Across 9,658 React sites, 44.8% use 0 iframes (84% good CLS), 25.7% use 1 iframe (84%), and 8.0% embed 4 or more iframes (70% good CLS).
By Arjen Karel · 212,308 crawled sites (70,213 with desktop Chrome field data, 203,027 sites with iframe count per page, October 2026). How we measured.