Google: Page Size Growth Still Impacts Performance
▼ Summary
– Google experts discussed webpage size growth, noting the median mobile homepage increased from 845 KB in 2015 to 2,362 KB in 2025.
– They clarified Google’s crawl limits, mentioning a general 15 MB default per URL and specific limits like 2 MB for HTML files.
– Structured data was highlighted as adding page weight for machines, creating a tension between machine readability and user experience.
– Page size remains important as it impacts users on slow or metered connections, despite faster home internet speeds.
– The trend of growing page weight affects performance and accessibility, though most pages still do not hit Google’s crawl limits.
In a recent industry discussion, Google’s Gary Illyes and Martin Splitt examined the ongoing trend of increasing webpage size and its tangible effects on user experience and search engine operations. The conversation, which began by questioning whether websites are becoming “fat,” quickly clarified that the meaningful metric is individual page weight, not the size of an entire domain. This focus on per-page data is critical for understanding performance impacts.
Data from the 2025 Web Almanac illustrates a significant shift. The median mobile homepage has ballooned from 845 KB in 2015 to 2,362 KB this past July, representing a near tripling in size over a decade. While both experts acknowledged this growth is a natural byproduct of more complex web applications, the sheer scale of the increase was still notable. Splitt pointed out the inherent difficulty in even defining “page weight,” as interpretations vary between raw HTML, transferred bytes, or the total resources required for full browser rendering.
Regarding Google’s systems, Illyes explained the 15 MB default crawl limit applied across its infrastructure, where each URL is assessed individually and referenced assets are fetched separately. This figure differs from the documented limits for Google Search’s specific crawler, which processes the first 2 MB of a supported file type. These technical boundaries are not rigid, however, as internal teams possess the flexibility to adjust them based on crawl targets, a topic covered in a previous episode.
A particularly insightful part of the dialogue addressed structured data and potential bloat. Illyes reflected on a historical perspective from Google co-founder Sergey Brin, who believed machines should interpret content from text alone. He noted that structured data serves machines, not users, and implementing the full spectrum of supported types can add invisible weight to a page. This creates a clear tension between providing machine-readable signals and maintaining lean page performance.
Does page size still genuinely matter for performance? Splitt affirmed that it does. While his personal high-speed connection makes page weight a non-issue, experiences with slower networks or metered satellite internet while traveling provide a starkly different reality. He suggested that the growth in page size may have outstripped gains in median mobile connection speeds, though verifying this would require deeper data analysis. Illyes added that prior industry studies consistently link faster websites with improved user retention and higher conversion rates.
Looking forward, Splitt indicated plans to explore specific techniques for reducing page size in a future session. For now, while most pages remain well below Google’s crawl limits, the persistent upward trend in page weight has real consequences. It directly affects site performance and accessibility for the substantial number of users relying on slower or metered internet connections around the world.
(Source: Search Engine Journal)
