Indexing is the process in which a search engine analyses a fetched page and stores it in its database, the index. Only pages in the index can appear in search results. Indexed doesn't mean well ranked, it just means: Google knows the page and can display it.
What indexing means
Google describes search as a process in three steps. First, crawling: a program, the Googlebot, fetches pages it knows about through links, sitemaps or previous visits. Then rendering and indexing: Google runs the page like a browser, reads text, images, headings and structured data, checks whether the page is a duplicate of another, and stores the result in its index. Finally, serving: for a search query, Google selects the most suitable pages from the index and ranks them.
The index is Google's directory of the web. A page that isn't in it doesn't exist for search, no matter how good it is. Conversely, being in the index only means that the page can be displayed in principle. Where it ends up is decided by the evaluation in the third step.
You can check whether a page is indexed. The quick way is a Google search for «site:your-domain.ch/page». The URL inspection in Search Console is more reliable. It shows whether and when Google last fetched the page, whether it's in the index and which address is considered canonical. The «Page indexing» report also lists all pages Google knows about but hasn't included, along with the reason. How to set up Search Console is explained under Setting up Google Search Console.
An example from everyday SME life
A driving school in Frauenfeld publishes a post on how many driving lessons you need before the test. After four weeks, the post can't be found on Google. The owner assumes the text must be poor.
The URL inspection shows something else: «Crawled, currently not indexed». Google has seen the page but not included it. The post is only linked from the blog overview, and that overview isn't reachable from any other page. The driving school adds a link to the post from the homepage and from the «Prices» page, and resubmits the address in Search Console. Two weeks later, it's in the index and appears on the first page.
Why this matters for your business
Many visibility problems are actually indexing problems. Pages are written, published and never picked up by Google because a noindex was forgotten, the page isn't linked anywhere, or it looks too similar to another one. Before you fine-tune your text, it's worth checking whether Google even knows the page exists.
Search Console gives you this answer for free. What you can do if a page appears there as not indexed is described in the post Page not indexed.
Common misconceptions
Indexed means found. No. Indexed means stored. A page is only found once it ranks high enough for relevant searches.
Google indexes everything it crawls. Google decides after fetching whether a page deserves a place in the index. Thin, duplicate or noindex pages stay out.
Frequently asked questions
How long does it take for Google to index a new page?
That ranges from hours to several weeks. Websites that publish regularly and are well linked get crawled more often. An XML sitemap and an internal link from a well-visited page speed up the process. Google doesn't name a fixed timeframe.
What does «Crawled, currently not indexed» mean?
Google has fetched the page but decided not to include it for now. Common reasons are thin content, strong similarity to other pages, or a website Google generally rates as not very relevant. Strengthening the content and improving internal linking usually helps.
Is an indexed page automatically visible on Google?
It can be displayed, but its position is decided by the evaluation in the third step, the serving of results. An indexed page at position 60 is effectively invisible. Indexing is the entry ticket, not the seat.