In a joint announcement, Google and Bing have declared an increase in the limit of sitemap file sizes from the standard 10 MB to 50 MB.
Most sitemaps never reach the 10 MB file size limit, but larger sitemaps are still occasionally encountered. This can happen when sitemaps contain very long URLs or attributes with long URLs, such as image URLs and alternate language URLs.
Now, larger sitemaps will no longer be an issue as long as they stay under 50 MB. It’s important to note that sitemaps can still be compressed using gzip to reduce file size based on bandwidth limits. However, once unzipped, the sitemap still cannot exceed 50 MB.
This change impacts sitemap file size only and does not affect the limit on the number of URLs that can be contained in a sitemap, which remains at 50,000. It is recommended to limit your sitemap to include only relevant pages, not only to keep it under 50,000 URLs but also as an SEO best practice.
Keep in mind that although your sitemaps can now be up to 50 MB in size, smaller sitemaps can prevent your server from becoming overloaded. If Google frequently requests a 50 MB sitemap, it could place unnecessary strain on your server.
For more information on best practices and advice for large sites, refer to resources on sitemap best practices.
