What is noindex?
Noindex is an instruction to search engines that a page should not appear in search results. It is set either as a robots meta tag in the HTML (<meta name="robots" content="noindex">) or as an X-Robots-Tag: noindex HTTP header. Google treats noindex as a directive, not a hint: once it crawls the page and sees the tag, it drops the page from the index.
Noindex is the reliable way to keep a page out of Google. It is the right tool for thank-you pages, internal search results, thin tag archives, staging content, and any page that is useful to visitors but has no business ranking.
How it works
The key detail is that a crawler has to fetch the page to see the noindex. That makes noindex and robots.txt a bad combination. If robots.txt blocks a URL, Google never reads the page, never sees the noindex, and can still index the bare URL if other sites link to it. To remove a page from results, allow crawling and set noindex.
Removal is not instant. The page leaves the index the next time Google recrawls it, which can take days or weeks for low-priority URLs. For urgent cases, Search Console's Removals tool hides a URL temporarily while the noindex takes effect.
Noindex pages can still pass link signals for a while, but Google has said that a page left on noindex long term is eventually treated like noindex, nofollow, so do not rely on noindexed pages as link hubs.
Example
The meta tag version goes in the <head>:
<meta name="robots" content="noindex, follow" />
follow is the default, so noindex alone means the same thing. For non-HTML files such as PDFs, which have no <head>, the header version is the only option:
X-Robots-Tag: noindex
In WordPress
Checking Settings → Reading → Discourage search engines from indexing this site makes WordPress add noindex to every page, which is correct on staging and disastrous if left on after launch. SEO plugins add per-type and per-post control. In Hydrogen SEO, the Robots screen sets Noindex per post type and taxonomy, the SEO Settings sheet overrides it per post, and author archives, search results, and the 404 page get noindex, follow automatically. See robots meta settings.
Common mistakes
- Launching with "Discourage search engines" still checked. Traffic falls to zero over a few weeks.
- Blocking a noindexed page in robots.txt, so the tag is never read.
- Listing noindexed URLs in the XML sitemap, which asks Google to crawl pages you then tell it not to index.
- Noindexing a page and canonicalizing it elsewhere at the same time. Pick one signal.
Common questions
How long does noindex take to work?
Until Google recrawls the page. Important pages are often recrawled within days; rarely visited ones can take weeks. Requesting indexing in URL Inspection can speed up the recrawl.
Is noindex the same as disallow in robots.txt?
No. Disallow stops crawling but not indexing. Noindex stops indexing but requires crawling. Use noindex when the goal is to keep a page out of results.