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// SEO Guides

XML Sitemap Tags Explained: Priority, Changefreq, and Lastmod

When you open an XML file, you will notice several different tags attached to every URL. Some are required, while others are entirely optional. Understanding how these tags work will help you structure your data correctly for search engines.

It is very easy to make formatting mistakes when writing these tags manually. We highly recommend using a sitemap XML tester to ensure your values meet the strict requirements before submitting to Google.

Let's break down the three most common metadata tags.

1. <lastmod> (Last Modified)

This is the most important optional tag. It tells search engines exactly when the content on the page was last updated. Google relies heavily on this tag to decide if it needs to re-crawl a page.

If you update an article but forget to update the <lastmod> date, Googlebot might ignore the changes.

  • Format: It must be in the W3C Datetime format (usually YYYY-MM-DD).
  • Example: <lastmod>2026-08-28</lastmod>

2. <changefreq> (Change Frequency)

This tag provides a hint to search engines about how often the content at a specific URL is likely to change. It is only a hint, not a strict command. Googlebot will still crawl based on its own algorithms, but this tag helps guide its initial schedule.

You cannot just invent words for this tag. The protocol only allows a strict list of values:

  • always
  • hourly
  • daily
  • weekly
  • monthly
  • yearly
  • never

3. <priority>

The priority tag lets you indicate the importance of a specific URL relative to other URLs on your own site. It does not affect how your pages compare to other websites in search results. It simply tells Google which pages you think are the most critical.

  • Format: A number between 0.0 and 1.0.
  • Default: If omitted, search engines assume a priority of 0.5.
  • Example: Your homepage might be <priority>1.0</priority>, while your privacy policy might be <priority>0.1</priority>.

Note: Google has publicly stated they largely ignore the priority and changefreq tags in modern indexing, focusing instead on internal links and the lastmod tag. However, Bing and other engines still use them.