Does a “last modified” date in the sitemap affect re-crawling?
- Published November 6, 2026
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It can, as long as Google trusts it. Google’s sitemap documentation says it uses the lastmod value when it is consistently and verifiably accurate, for example when it matches the last modification of the page. A date that moves only when the page really changes gives Google a reason to revisit that URL. A date that changes on every page every day gives Google nothing to go on, and by the documentation’s own condition it stops being a value Google relies on.
What “verifiably accurate” means in practice
Google can compare the date you report with what it finds when it fetches the page. If the sitemap says a page changed yesterday and the page is identical to the version Google already has, the date has failed that check. Repeat that across the site and the field can lose its usefulness more widely, which is an inference from the “consistently” condition: Google does not say exactly how it treats a site whose dates are only partly reliable, and it describes no penalty, only a value it may stop using.
| Practice | Effect on the <!–INLINECODE1–> signal |
|---|---|
| Date changes when the main content changes | Usable: the date matches what Google finds |
| Date changes for a typo fix or a new related-posts widget | Weak: the page barely changed; Google sets no exact threshold, so tie the date to changes in the main content |
| Every URL stamped with today's date on each build | Unreliable: the dates cannot be verified against real changes |
| No <!–INLINECODE2–> at all | Neutral: Google relies on its other signals for when to recrawl |
The fields Google ignores
The same documentation says Google ignores the priority and changefreq values. Setting every page to priority 1.0 or “daily” does not change how often Google crawls, so the only date-related field worth maintaining is lastmod.
How to set it up
- Tie
lastmodto the date the main content was last edited, not the date the sitemap was generated. - Exclude template-wide changes, such as a new footer or a sitewide design tweak, unless they change what the page says.
- Spot-check: pick a few URLs with recent dates and confirm the page content really changed on that day.
On a small site the field matters less: Google’s Crawl Stats help says a site with fewer than a thousand pages should not need to worry about that level of crawling detail. Google’s crawl budget guidance describes which sites need to think about crawl priority at all, and whether your sitemap should include every URL or only the important ones deals with what else belongs in the file. Whether a sitemap gets pages indexed or only found is a separate question, answered in whether a sitemap is enough to get pages indexed. On a large site the field earns its keep: an accurate date helps Google find the pages that changed among the many that did not, so tie it to real edits and leave it alone otherwise.
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