What is the sitemap size limit?

A single sitemap file can contain at most 50,000 URLs and must be no larger than 50 MB when uncompressed. If your site has more pages, split the addresses across several sitemap files and list them in a sitemap index file. These limits come from the sitemaps.org protocol, which Google and Bing both support.

Why it matters

A file that goes over either limit may be rejected or only partly used, which leaves some of your pages out of the list you meant to give search engines. Knowing the limits also tells you when it is time to move from one sitemap to an index with several.

How to check

Download your sitemap. If it is compressed as a .gz file, unpack it, because the 50 MB limit applies to the uncompressed size. Compressing the file saves transfer time but does not raise the limit.
Count the URLs. On a terminal, this counts the loc tags:

curl -s https://www.example.com/sitemap.xml | grep -o "<loc>" | wc -l

Check the size of the unpacked file:

curl -s https://www.example.com/sitemap.xml | wc -c

Divide the result by 1,048,576 to get megabytes.

If the file is near either limit, split it. A sensible approach is one sitemap per section, such as posts, products and pages, so a problem in one section is easy to spot.
Create a sitemap index that lists each child file, and submit the index address in Search Console. A sitemap index can itself list up to 50,000 sitemaps.
Look at the Sitemaps report after submitting. Each child sitemap shows its own status and page count.

Splitting early is fine. There is no rule that a sitemap must be full before you create a second one, and smaller files are quicker to generate and easier to troubleshoot.

Common mistakes

Measuring the compressed size and assuming the limit is met.
Padding the sitemap with redirected, duplicate or parameter URLs, which uses up space on pages you do not want indexed.
Splitting files but forgetting to create the index or to submit it.
Listing one index inside another. An index should list sitemap files, not further indexes.
Letting a plugin keep growing a single file with no cap.

Frequently asked questions

Does gzip change the limit?

No. The file can be served compressed to save bandwidth, but the 50,000 URL and 50 MB limits are measured on the uncompressed content.

Do I need a sitemap index for 10,000 pages?

Not for size reasons, since one file can hold 50,000. You might still choose an index to separate sections of the site and make reports easier to read.

Do image and video entries count?

Extensions for images and video add data inside each entry, so they add to the file size. Watch the 50 MB limit if you use them heavily.

To see how your own site is set up, Try the free website sample.