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 CLS, against 88% of all sites.
57.0% of sites have no iframe count per page. Of the 43.0% that do, 40% use 2 to 3 iframes, and 95% of those sites have a good INP, against 95% of all sites.
57.0% of sites have no iframe count per page. Of the 43.0% that do, 40% use 1 iframe, and 82% of those sites have a good LCP, against 82% of all sites.
Core Web Vitals pass rate
Sites with 1 iframe iframe count per page have a good CLS most often: 86%, against 88% of all sites. Sites with 4+ iframes iframe count have it least often, at 81%.
Sites with 2 to 3 iframes iframe count per page have a good INP most often: 95%, against 95% of all sites. Sites with 4+ iframes iframe count have it least often, at 92%.
Sites with 1 iframe iframe count per page have a good LCP most often: 82%, against 82% of all sites. Sites with 4+ iframes iframe count have it least often, at 78%.
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 114,908 sites (57.0%) with 0 iframes, 90% pass field CLS. Adding 1 iframe (17.4%) lowers good CLS to 86%, 2 to 3 iframes (17.3%) drops good CLS to 86%, and 4 or more iframes (8.3%, 16,785 sites) pulls good CLS down to 81%.
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 (90% good CLS) versus 8.3% with 4+ iframes (81% 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 65,509 sites WordPress pages embedding 4+ iframes (9.1%) pass field CLS at 80% vs 92% with 0 iframes.
Across 65,509 WordPress sites, 53.6% embed 0 iframes (92% good CLS), 16.2% embed 1 iframe (87%), 21.2% embed 2 to 3 (87%), and 9.1% embed 4+ iframes (80% good CLS).
Shopify 8,573 stores 79% of Shopify stores embed iframes, with 4+ iframe stores (17.9%) passing CLS at 89%.
Across Shopify storefronts, 21.3% have 0 iframes (96% good CLS), 32.5% have 1 iframe (96%), 28.3% have 2 to 3 (93%), and 17.9% have 4+ iframes (89% good CLS).
React & Next.js 9,570 sites React & Next.js sites with 4+ iframes (8.0%) pass field CLS at 85% vs 93% with 0 iframes.
Across 9,570 React sites, 44.8% use 0 iframes (93% good CLS), 25.7% use 1 iframe (94%), and 8.0% embed 4 or more iframes (85% good CLS).
Wix 5,825 sites Wix sites without iframes (42.5%) pass CLS at 99%, compared with 97% on sites with 2 to 3 iframes.
Across 5,825 Wix sites, 42.5% use 0 iframes (99% good CLS), 31.3% use 1 iframe (97%), and 20.7% use 2 to 3 iframes (97% good CLS).
By Arjen Karel · 210,902 crawled sites (196,263 with all devices Chrome field data, 201,622 sites with iframe count per page, October 2026). How we measured.