What Does Indexed Not Submitted in Sitemap Mean?
When going through your Google Search Console, you might find that some of your pages are marked as Indexed, not submitted in sitemap and wonder what this means. Thankfully this is nothing to be alarmed of and will not cause any adverse affects on your SEO.
So, what does index not submitted in sitemap mean? This simply means that Google found and indexed a page on your site that is not included in your sitemap. There is nothing wrong with having pages with this status. If anything, it's a good thing that Google found additional pages on your site.
There is a misconception that you must have a sitemap submitted to Google in order for them to see all your pages. While adding a sitemap certainly doesn't hurt, it doesn't mean that you have an advantage either.
Truth be told, Google actually doesn't even crawl your sitemap every time it craws the site. Therefore, when crawling the site, it may come across an addition page that it didn't see on your sitemap before, and give the page this status.
Sitemaps are most beneficial for large websites with many many pages as it can help ensure that Google doesn't miss any of them. But if you just have a small website with a handful of pages, it won't make that much of a difference whether you have submitted a sitemap or not.
What To Do If You See Indexed Not Submitted to Sitemap
If you have submitted a sitemap and Google still found pages outside of the sitemap, it's an indication that your sitemap is outdated and you need to submit a fresh copy.
First you should check the current sitemap to make sure that the page is indeed listed. You can usually do this by just adding /sitemap.xml to the end of your domain name and the sitemap should populate if available.
Once you've confirmed this, you can resubmit it to Google Search Console simply by just submitting it again. You don't need to remove the sitemap that is already added, just submit a sitemap as if you are submitting a brand new one. This will simply refresh the sitemap you have already added and let Google know that there is a fresh copy to crawl.