Third-Party Script Performance Statistics 2026
A scoreboard of what third-party scripts actually cost your loading score, ranked by measured LCP impact from real-user field data. Every category links to the full study behind the number.
Last updated July 2026 from the May 2026 CrUX release.
The headline numbers
The Average Page Loads 375KB of Third-Party JavaScript.
A/B Testing Tools Cost 10.2 Points of Good LCP - the Worst of Any Third-Party Category.
Live Chat Costs 9.5 Points of Good LCP.
Google Fonts Costs 9 Points of Good LCP.
Social Embeds Cost 8.6 Points of Good LCP.
The growth problem
Source: HTTP Archive Web Almanac JavaScript chapters, 2020, 2022, and 2024 editions.
50th-percentile values across the HTTP Archive mobile crawl. CNAME-cloaked third parties are not included, so figures are a lower bound.
The Average Page Loads 375KB of Third-Party JavaScript.
Cost by category (measured LCP hit)
Source: PageSpeed Matters analysis of 9.5 million origins with CrUX field data, mobile 75th percentile, mid-2026. Bars scaled to the largest penalty.
A/B testing sits at the top of the list. The anti-flicker snippet is the reason its loading cost outruns every other named tool.
A/B Testing Tools Cost 10.2 Points of Good LCP - the Worst of Any Third-Party Category.
Live Chat Costs 9.5 Points of Good LCP.
Google Fonts Costs 9 Points of Good LCP.
Social Embeds Cost 8.6 Points of Good LCP.
GTM Costs 5.3 Points of Good LCP - and Barely Moves Anything Else.
Cookie Banners Cost 3.7 Points of LCP - Yet Those Sites Pass Core Web Vitals More Often.
Download the data
Every stat on this page with its sample size, source, and study URL.
Cite this page
Third-Party Script Performance Statistics 2026. PageSpeed Matters. https://www.pagespeedmatters.com/resources/statistics/third-party-scripts
Every statistic here comes from an original study with full methodology, charts, and a downloadable dataset.
Browse all data studies