Internal links: what they are, types and how to use them

Internal links are the links that take you from one page of your website to another page on the same site: the menu, the breadcrumbs, the related products and that "read also" someone left in an article. It sounds like the most basic part of SEO, and on a small website it is.

On large sites things change. Every time we crawl an enterprise site for the first time we measure click depth by page type, and the pattern repeats across industries: the pages the business needs to sell end up 5, 6 or 7 clicks from the home page, while a blog post from 2019 sits comfortably at 2. Nobody decided it that way. It just happened, template by template, year by year.

My take is that on a large site internal linking is decided in the templates, so you work it by measuring depth by page type rather than adding links article by article. Here I start with what everyone should know about internal links (what they are, what they do for SEO, types and anchor text) and then I walk you through the strategy we use to organize them when a website has hundreds of thousands of URLs.

What are internal links?

An internal link is a hyperlink that connects two pages on the same domain. Internal links can live in the template (the menu, the footer) or inside the content of a page. If you are on a product page and click on its category, you followed an internal link. If you click on an article on another site, you followed an external one.

There is a technical detail worth getting clear from the start. For Google, a link only counts as a link if it is built with the <a> tag and an href attribute pointing to a real URL. Google's link best practices say it pretty directly: generally, Google can only crawl your link if it is an <a> element with an href. A button that navigates with JavaScript can work perfectly for the user and be invisible to the search engine, so those do not count as internal links for SEO.

How are they different from external links and backlinks?

Backlinks get almost all the attention (and the budget), but internal links are the only ones you can change today, without asking anyone for permission and without paying a publisher. External links matter too: citing a good source gives the reader context and backs up your content, although we will not cover that part here.

Why do internal links matter for SEO?

Internal links matter for four reasons, and it helps to separate them because each one is worked differently.

1. Google discovers your pages by following them. Googlebot lands on a URL, reads the links it finds and adds them to its list of things to crawl.

Google's SEO starter guide sums it up: Google finds pages mainly through links from other pages it has already crawled.

The sitemap helps, but it does not replace links: a URL that only exists in the sitemap and that nobody links to is telling Google that not even you consider it important.

2. They distribute authority within the website. The idea comes from PageRank, Google's original algorithm, which measures a page's authority based on the links it receives.

Each internal link passes part of that authority to the destination URL (what the industry calls link juice). The pages with the most authority are usually the home page and the ones that earn backlinks, so what you link from there carries more weight.

Be careful with guides that calculate the split with exact numbers ("a URL worth 100 that links to 4 passes 25 to each"). Google stopped showing public PageRank in 2016 and nobody outside Google knows today's formula, so those authority calculations work as intuition and that is about it.

3. They explain the site's structure and hierarchy to Google. A category that gets links from 5,000 product pages tells Google it is a central page. An article that gets none tells it the opposite, however good its content is. Google itself asks that every page you consider important be linked from at least one page on your site, and internal links are the most direct way to do that.

4. They help the user. A good internal link answers the reader's next question before they go back to Google to look for it on another site, and clear navigation gets them where they want in two clicks. That is basic user experience, and it is also what lets a visit to a blog post end on a service page.

What types of internal links are there?

For SEO, internal links fall into two big families, and the difference between them is what matters most on large sites:

Navigational links are the ones in the main menu, the footer, the breadcrumbs and the pagination of listings. They come from the template, so a change in the footer or the breadcrumbs repeats across thousands of URLs at once. In practice, navigation is the structure of the website that Google sees.

Breadcrumbs are a good example of an underrated template link, and they give categories authority without touching the content. As I explain in my breadcrumbs guide for Ahrefs in Spanish, each crumb is a link pointing up: if you have 5,000 products with breadcrumbs, your category pages get 5,000 internal links without anyone adding them by hand. And since January 23, 2025 Google no longer shows them in mobile results, so today their value lies more in the linking than in how your result looks.

Contextual links are the ones inside the content, with an anchor text that describes the destination page. They are the ones people discuss most when talking about internal linking and the ones that help the reader most, because they show up right where the content needs them, but they move one page at a time. On a blog with 80 articles that is enough. On a catalog of 200,000 URLs, not so much.

How do you build an internal linking strategy?

This is the SEO strategy we use on large sites. On a small website you can skip step 4 and do everything by hand.

1. Define which pages matter to the business. The ones that sell (categories, services, quote tools) and the pillar pages for each topic. That list is your priority, and it rarely matches the URLs that get the most internal links today.

2. Measure click depth by page type. Crawl the whole site with a tool like Screaming Frog and calculate the average per template: product, category, article, landing page. The number that matters is the average by page type, because that is where you see which template is burying which.

3. Set a simple rule. Ours is everything commercial at 3 clicks or less from the home page. It is easy to explain to a manager and very easy to audit afterwards.

4. Work on the template modules. Related-item blocks on product pages, topic hubs that group buried inventory, complete breadcrumbs and pagination that keeps the deep catalog within crawl reach.

5. Add contextual links where they help. From content with traffic and backlinks, which tends to concentrate authority, to the service pages on the same topic, and between pieces in the same content group (the pillar page and its satellites, what on this blog we explain as a silo structure).

6. Crawl again and compare. Depth distribution by template before and after, alongside the crawl stats in Search Console.

Let's look at step 4 with an example (made up, so the numbers are visible). You have a catalog of 200,000 URLs and 30% of the commercial inventory sits more than 4 clicks deep. A single topic-hub module, 60 hubs with 40 links each, repositions 2,400 pages with one template change. Doing the same by hand, link by link, is months of work nobody is going to finish.

It is the same logic as with SEO titles: on a large site, a well-made template decision moves thousands of URLs, and so does a bad one.

Now, any internal links strategy deserves realistic expectations. Patrick Stox described on the Ahrefs blog how they tested a related posts section on their own blog: the result was a slight lift, and his explanation is that they already linked well internally. In other words, internal links pay off most where the structure is weakest, and that is exactly what measuring depth helps you find.

How many internal links should a page have?

There is no magic number, even though it is the most repeated SEO question on the topic. Google says it plainly: there is no exact number of links a page should contain, but if you think it has too many, you are probably right.

Some guides suggest rules like 3 to 5 contextual links per 1,000 words. They work as a reference so you do not overdo it, but I would ask a different question: does this link help the reader at this point in the text? If the answer is yes, it stays. If it is only there to "pass authority", the reader notices and Google probably does too, so I prefer a few internal links the reader actually uses.

How should you write anchor text?

Anchor text is the text you click on, and in internal links it is one of the few signals you control word by word. Google asks for it to be descriptive, concise and relevant to the page it is on and to the page it links to.

A couple of examples:

• Generic: "To learn more, click here." That anchor text says nothing about the destination page.

• Descriptive: "Check how to measure crawl budget before opening the project." It makes sense on its own, even outside the paragraph.

The test Google suggests is very practical: read only the anchor text, out of context, and see whether it is clear where it leads. Three more rules worth following:

• Use the destination page's keywords when they fit. If the page is called "Travel insurance for Europe", an anchor like "travel insurance for Europe" is the natural choice.

• Vary without changing the topic. Ten identical exact-match anchors sound forced; ten anchors naming different topics for the same URL are confusing.

• Do not chain links. Google mentions this too: two links stuck together are hard to tell apart and you lose the text around each one.

Which internal linking mistakes should you check?

These are the ones I would check first, in this order:

• Broken links. Internal links pointing to a 404. It happens a lot after a redesign, when a category URL changes and the template keeps pointing to the old one.

  If the broken link sits in the footer, the problem multiplies across every page of the website.

• Links to redirects. The internal link goes to a URL that redirects to another. It works for the user, but every redirect is an extra hop for Googlebot. The fix is to point straight to the final URL.

• Orphan pages. Pages that exist (they are in the sitemap or get traffic) but that no other page links to. They tend to be old campaign landing pages, content someone published and never linked, or product pages left out of the categories. A page nobody links to gets zero internal authority.

• Nofollow on internal links. The nofollow attribute asks Google not to follow that link. On external links it makes sense; on internal ones it is almost always a leftover from an old practice that today only cuts the path to your own pages.

• Links Google cannot follow. JavaScript buttons without href, navigation dropdowns that only exist after a click, filters that load without changing the URL.

• Too many links to what does not matter. This is the most expensive one on large sites. An example (also illustrative): a site with lots of content and catalog gets 1,000,000 Googlebot visits a month and, when you check the logs, 38% go to filters and parameters you do not even want indexed. That crawling comes from internal links some template is generating. If this sounds familiar, the crawl budget article explains how to size it.

How do you audit your internal links?

To audit internal links, three sources cover almost everything:

1. The Links report in Search Console. It shows the URLs with the most internal links according to Google, a good approximation of where you are sending authority. It works as a first look: if your commercial pages are not near the top and your blog content is, you already have a clue.

2. A crawler. Screaming Frog or Ahrefs Site Audit go through the site the way a search engine does and give you the depth of every URL, the broken links, the redirects and the URLs with no incoming links. Cross the crawl with the sitemap and with the URLs that have impressions in Search Console: what shows up there and not in the crawl are your orphan pages.

3. Server logs. On large sites they are the only way to see what Googlebot is really crawling, which is not always what the sitemap says.

With that you put together an SEO audit of internal links you can repeat every quarter, or after every big template change. If you are planning a redesign, it is worth adding it to the website redesign checklist.

What I would check this week

If you have an hour and a crawler, I would do only this: take the 10 pages that matter most to the business and see how many clicks from the home page they are. If any is deeper than 3, you know where to start your strategy, and the fix is probably in a template and not in an article.

The rest can wait. Internal links are one of the few things in SEO that depend 100% on you and your website, so it is worth making them point to where the business is and not just to your oldest content.