Hyperlinks that link to subpages within a domain are described as "internal links". With internal links the linking power of the homepage can be better distributed across directories. Also, search engines and users can find content more easily.
Intent and purpose of internal links
Internal linking fulfills multiple purposes at once. It makes sense for Google & co. as well as for users.
- For search engines: If you assume that only a fraction of all URLs of a medium-sized website are linked from the outside via backlinks, then it becomes clear that the internal link structure does an important job at this point. As soon as the Googlebot or another search engine visits a website, it follows the links found according to the instructions in . Here the anchor text is also read out and interpreted. The internal links give the bot information and deliver to the crawler the topical connection of the subpages within a domain. Thanks to the frequency of internal links and their link texts the bot can, for example, recognize why a certain subpage is more relevant to a given search term; even without an external backlink referencing the corresponding page.
- For users: Internal links are visible for users, e.g. as a main navigation or in a breadcrumb structure. This speaks to a primary utility of internal linking for users: Orientation. At the same time, links with a website offer the opportunity to draw attention to further topics or additional content. This is also likely to lead to users remaining on a site for longer periods. This user signal can, in turn, have a positive impact on the classification of a website by search engines. A classic example for successful internal linking is Wikipedia where a visitor to an article is directed to a corresponding “offer” to find out more information with one click.
This characterizes good link structure
With the help of internal links the topical assignment of subpages as well as the navigation of the users can be optimized. To ensure the link structure makes sense, webmasters and SEOs should pay attention to the following aspects:
- Ideally, internal links should not be in the footer or the sidebar.
- The ideal location of internal links is at the start of the a page, so that a click of the respective link can actually take place.
- The anchor text of an internal link should be made up of the central keyword of the target page or give the user and the search engine a clear idea of the link target.
- The internal links of a website should differentiate themselves from the rest of the text with italics/bold and/or underlining.
- Internally set links should match the topic of the linking page and take up, expand on or add to the topic by linking.
- The internal links should also actually be clicked by users.
- The quantity of links used within the page should be limited to a sensible amount per subpage, so that the ideal amount of link juice is passed on.
- The link goal should always be linked with the same keyword within the domain.
The difference between internal, incoming and outgoing links
Whilst search engines such as Google have set up corresponding spam filters for backlinks via the search algorithms, this limitation does not apply to the internal hyperlinks. This means that nowadays, for example, the use of “hard” keyword links should be avoided in external links so as not to receive a penalty from Google.
In internal linking it is of particular importance to use the keywords in the link text so that search engines can better orientate themselves within the website.
Unlike with outgoing links, internal linking problems such as do not need to be worried about given that it is possible to link from every point of the domain to every arbitrary URL within the domain.
FAQ on internal links
How many internal links should a website have?
For a long time the rule was that no more than 100 links should be found on a URL. But there is no actual limit. However, the crawl budget of the Googlebot is limited by the number of internal links of a URL. Basically, the more crawl budget is available for a URL, the more internal links can be set.
Is there a Google penalty if I only use keyword links internally?
No, unlike incoming backlinks, there is no limitation on internal linking. In fact, it is precisely keyword links that should be used.
Are the links in the main navigation not sufficient?
The most important categories of a website are generally reached via the main navigation. In order to make reference even in the deepest directories, internal links should also be set in the content.
Is internal linking worthwhile even on small sites?
How do I create internal links on a one-pager?
Search engines can sometimes read JS, however, normally the links in the script are not taken into account for internal linking.
What happens if I link to a URL that is forwarded?
If an internal link points to a forwarding link, it is not initially considered an error. However, two things should be kept in mind: The link loses a little “link juice”, even if it is not much, and should the forwarding be permanent, then the status code is 301 (and not 302 or 307).