---
title: "The Average Website Loads 375KB of Third-Party JavaScript - PageSpeed Matters"
url: https://www.pagespeedmatters.com/resources/data-studies/third-party-javascript-growth
description: "Third-party JavaScript on the median mobile page grew from 255 KB in 2020 to 375 KB in 2024, roughly two-thirds of all JS on a typical page."
lang: en
---

The Average Website Loads 375KB of Third-Party JavaScript (https://www.pagespeedmatters.com/resources/data-studies/third-party-javascript-growth)

Third-party JavaScript on the median mobile page grew from 255 KB in 2020 to 375 KB in 2024, roughly two-thirds of all JS on a typical page.

Median third-party JavaScript on the mobile page (KB)

2020

255 KB

2022

292 KB

2024

375 KB

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.

First-party vs third-party JavaScript on the median mobile page (KB)

First-party JS

168 KB

Third-party JS

375 KB

Source: HTTP Archive Web Almanac, 2024 JavaScript chapter.

External scripts outweigh first-party code by more than 2× on the typical page.

Source: The Average Website Loads 375KB of Third-Party JavaScript - PageSpeed Matters (https://www.pagespeedmatters.com/resources/data-studies/third-party-javascript-growth)