by Juan Robin II
Internal links are to backlinks what Robin is to Batman. They’re crucial to SEO success, yet receive little to none of the credit.
What are internal links, I hear you ask?
They’re links from one page on the same domain to another.
Every website has them. But what most people don’t realize is that—when used strategically—internal links can significantly boost a site’s performance in the search engines.
In this case study, Ninja Outreach explains how they used internal links to help boost organic traffic by 40%—a stat that’s backed up by our organic traffic estimates for ninjaoutreach.com:
In this post, you’ll learn why internal links are critical to SEO success and how to create a smart internal linking strategy for your website.
Why internal links are important for SEO
Google uses internal links to help discover new content.
Let’s say that you publish a new web page and forget to link to it from elsewhere on your site. If we assume that the page isn’t in your sitemap, and doesn’t have any backlinks, then Google won’t know it exists. That’s because their web crawler can’t find it.
Here’s what Google says:
Google must constantly search for new pages and add them to its list of known pages. Some pages are known because Google has already crawled them before. Other pages are discovered when Google follows a link from a known page to a new page.
Pages with no internal links pointing to them are known as orphan pages—more on those later.
Internal links also aid the flow of PageRank around your site. That’s a big deal. Generally speaking, the more internal links a page has, the higher it’s PageRank. However, it’s not all about quantity; the quality of the link also plays a vital role.
Here’s a simplified view of how PageRank works:
a note on pagerank
Google axed public PageRank scores in 2016. However, PageRank remains a core part of their ranking algorithm. We know this because they said so.
This is likely part of the reason Google states that:
The number of internal links pointing to a page is a signal to search engines about the relative importance of that page.
Google also looks at the anchor text of internal links to better understand context, as confirmed in this tweet by John Mueller:
Most links do provide a bit of additional context through their anchor text. At least they should, right‽
— 🍌 John 🍌 (@JohnMu) November 23, 2017
In other words, say that you have a page about blue widgets. You have multiple internal links pointing to that page with anchors like widgets, blue widgets, and buy blue widgets. Those help Google to understand that the page:
- Is about blue widgets, and thus:
- May deserve to rank for blue widgets and other relevant terms.
Notice that I bolded the word “may” there?
Just because your page is about a particular topic doesn’t necessarily mean that it deserves to rank for related keywords.
Google also states that internal linking structure can affect sitelinks. Not a huge deal, but something to keep in mind nonetheless.
Now, at this stage, you might be thinking “so if I wanted to rank for blue widgets, I should probably just add as many internal links as possible to that page with blue widgets as the anchor text, right?”
Kind of, but that way of thinking can lead to low‐quality and unnatural internal links.
Case in point:
You need to think smarter, and it all begins with your initial site structure.
How to set up the ideal internal link structure
Think of your website as a pyramid with the most important content at the top and the least important content at the bottom.
Most websites have the same page at the top of the pyramid—their homepage. Under that, they have their next most important pages—about us, services, products, blog, etc. Under each of those, they have slightly less important pages—individual products and service pages, blog posts, etc.
But you shouldn’t link all pages on one level of the hierarchy to all pages on another.
You need to keep relevance in mind.
The art of siloing
Siloing is the grouping together of topically‐related web pages via internal links.
For example, imagine that we have a website about countries and cities with these pages:
You can tell that each page falls into one of two distinct groups:
- Pages about countries
- Pages about the cities in those countries
So this is likely how you would “silo” these pages:
Each country page acts as a “hub” and links to subpages about related cities (and vice‐versa). This creates a topic cluster—a group of interlinked pages all closely‐related to the same topic.
Three benefits of this are:
- Users will have an easier time navigating their way around your site
- Crawlers will have an easier time understanding your site structure
- More “authority” is transferred to your most important pages (because subpages link back to hub pages and vice‐versa)
But there’s another, often overlooked benefit—this kind of structure can help search engines to understand the context of your content better.
Let’s say that I have the following page: domain.com/squash
Is that page about butternut squash, or perhaps the sport, squash? Who knows?
Well, let me reveal that this page is part of the following silo:
Now, what do you think? 🙂
Another overlooked advantage of silo structure is that—because you’re linking to and from topically‐related pages—there usually are plenty of opportunities to do so using relevant anchor text.
For example, it makes total sense to link from a page about fruits and vegetables to one about butternut squash with “squash” as the anchor text.
You don’t have to shoehorn that link into an unrelated page as we saw earlier.
Looking to learn more? Read Bruce Clay’s infamous guide to SEO siloing.
How to audit your internal links for issues
Everything above makes sense. But unless you’re starting a site from scratch, things aren’t always as organized as you’d like.
That’s why you should audit your existing internal links before adding more to your site.
This isn’t as difficult as it sounds. The first step is to crawl your site in Ahrefs Site Audit tool.
Here’s how to do that:
There are ways to do some of the stuff mentioned below without crawling your site. I will mention these as we go along. However, if you’re an Ahrefs user, my recommendation is to set a crawl going to ensure that you have the freshest data to work with.
Once the crawl is complete, check for these five issues:
1. Broken internal links
Site Audit > Internal pages > 4XX page
This report shows you all broken internal pages on your site.
These are bad because they waste “link equity” and result in poor user experience.
I recommend sorting the “No. of inlinks” column from high to low to prioritize pages with lots of internal links pointing to them.
Here are a few ways to solve such issues:
- Reinstate the broken page at the same URL (if deleted by accident).
- Redirect the broken page to another relevant URL. Update or remove all internal links pointing to it.
If you’re opting for solution #2, you can see all the inlinks to the broken page by hitting the corresponding number in the “No. of inlinks” column.
It tells you the referring page and anchor text, which makes it easy to find and remove/update them.
Learn more in our full guide to finding and fixing broken links.
No time to crawl your site? Try this:
Site Explorer > enter your domain > Best by links > add a 404 filter > switch to “internal” links > sort by dofollow internal links
Note. You should also sort by nofollow internal links. All broken internal links should be fixed.
Just click on the number of internal links to see the actual links.
Using Site Explorer instead of Site Audit is useful for when you want to see broken internal links on a third‐party website without having to run a full crawl.
2. Internal links to redirected pages
Site Audit > Internal pages > 3xx redirect
This report shows you all redirected pages (3XX) on your site.
Sort by “No. of inlinks” (high to low) to prioritize the pages with the most internal links pointing to them.
It’s important to note that not all of these will be issues. For example, if you have internal links pointing to moved and redirected pages (e.g., http://domain.com/blog → https://domain.com/blog), then it’s likely nothing to worry about.
Still, there’s no harm in updating these redirects to remove the additional “link hop.”
Either way, be on the lookout for pages that redirect to something not‐so‐relevant.
Case in point:
That’s 20 internal links to a specific brand of shoes, which now redirects to a generic women’s footwear page. Even worse, if we click on the number of inlinks, we can see that the anchor text used for these links is “Jeffrey Campbell” (the name of the brand).
That’s misleading, and those links should be removed or updated.
You can also use Site Explorer to find redirected internal links.
Site Explorer > enter your domain > Best by links > add a 301 filter > switch to “internal” links > sort by dofollow internal links
Note. Once again, you should also check and fix nofollow internal links.
3. Lots of internal links to unimportant pages
Site Audit > Internal pages > 2xx
This report shows the working pages on your site.
Sort by “No. of inlinks” (high to low), then start by skimming this list. If you see unimportant pages with lots of internal links, remove them. It may even make sense to delete those pages.
Here’s the kind of thing that you can often find with this tactic:
This blog post is about what’s new in June. As it’s now January of the next year, chances are this page isn’t particularly useful or getting a lot of traffic, yet it still has 16 internal links.
I would be inclined to delete this page and remove the internal links.
You can also customize the columns and sort by the number of “dofollow” inlinks instead, which can be useful for filtering out things like login pages with lots of internal nofollowed links.
It may also make sense to look for non‐indexable pages with many internal links pointing to them—especially if they’re “dofollow.” You can do that using the Data Explorer in Site Audit with the following filters:
Unless these links are essential for navigation purposes, they serve only to waste “link equity.”
Furthermore, if pages are set to “noindex, follow,” Google will equate them to “noindex, nofollow” in the long‐term. The result is an effective break in the flow of “link juice” through these pages, so it’s best not to internally link to them with “dofollow” links.
This can also be done, to an extent, in Site Explorer.
Site Explorer > enter your domain > Best by links > add a 200 filter > switch to “internal” links > sort by dofollow internal links
Note. There’s no way to see whether a page is indexable in Site Explorer. You would need to use Site Audit for that.
4. Deep‐linked important pages
Site Audit > Internal pages > 2xx
This report shows the working pages on your site. Sort by “Depth” (high to low) to see the pages that are the most clicks (link hops) away from your seed page—which will likely be your homepage.
As a general rule of thumb, if you see any important pages—ones that earn you revenue, convert well, target a worthwhile keyword, etc.—more than three link hops from your homepage, then you may want to consider adjusting your internal linking structure to bring them closer.
A couple of reasons why this makes sense:
- Google may deem “deep” pages to be relatively unimportant—so they may not recrawl them too often. Not always an issue, but something to keep in mind.
- The most authoritative page on most sites is the homepage—the closer a page is to your homepage in terms of link hops, the greater the transfer of PageRank to that page.
5. Orphan pages
Site Audit > Internal pages > Incoming links > Orphan page (has no incoming internal links)
This report shows pages with no internal links, i.e., orphan pages.
For this to work, it’s crucial that you either specify your sitemap URL or leave the “Auto‐detect sitemaps” box checked when setting up a crawl. If you opt for the latter, Site Audit will only be able to find your sitemap if it’s listed in your robots.txt file or located at yourdomain.com/sitemap.xml.
No important pages should be orphaned for two reasons:
- Google won’t be able to find them (unless you submit your sitemap via Google Search Console, or they have backlinks from crawled pages on other sites).
- No PageRank will be transferred via internal links—as there are none.
Skim the list and make sure no important pages appear here.
If you have a lot of pages on your site, try sorting the list by organic traffic from high to low. Orphaned pages that still receive organic traffic would likely get even more traffic if internally linked to.
How to strategically use internal links to boost pages
Internal links aren’t the only means of increasing the authority (PageRank) of a page. Backlinks also help.
The pages with the highest authority—i.e., URL Rating (UR)—have tons of backlinks.
Yes, they’re also part of our overarching site structure and have internal links, but it’s the links from external sources that give these pages their power.
Which brings me to my point:
Internally linking from relevant, high‐authority pages to those that need a boost is a smart strategy.
There are a lot of ways to do this, and the methods can get quite elaborate and complicated (spreadsheets, VLOOKUPS, etc.).
So below, I’ll focus on two simple strategies that anyone and everyone can use.
Method #1 — Do a “site:” search
Let’s say that you’ve published a new blog about image SEO. (We did this recently, so we’ll stick with this example.)
You want to add a few internal links to that page to give it a boost.
But how do you know where to link from?
Start by searching in Google with the following search operator:
site:yourdomain.com “keyword or phrase related to page”
Here’s an example for “image SEO”:
This search returns pages on your site (in Google’s index) that mention a specific word or phrase.
You can see that in this instance, the phrase “image SEO” appears in six of our blog posts, including our WordPress SEO guide. However, if you look at the page itself, you’ll see that those words are unlinked.
Do you see where we’re going with this? That’s the perfect place from which to link to our image SEO guide with super‐relevant anchor text.
That’s what we did.
That’s not the only place from which we can link either. There are four other pages also mentioning that phrase—excluding the guide itself. So we can quickly check out those places, and add links where relevant.
You can also search Google for other keywords to find more relevant places from which to add internal links. For example, for our image SEO guide, we may also search for:
site:ahrefs.com/blog “alt text”
site:ahrefs.com/blog “google images”
Now, this process is fine as long as you have a small site—it didn’t take us long to check through six pages manually.
If you have a larger site, however, and see a lot of results for your query, it makes sense to prioritize and add links from the most powerful pages.
There are two ways to do this.
The second is to scrape the Google results using the Scraper Chrome extension (here’s the XPath to do that:
//div[@class="srg"]/div/div/div/div/a/@href), then paste them into Ahrefs Batch Analysis tool. Sort by UR.
Both methods achieve the same result.
We go through this process every time we publish a new blog post.
Method #2 — Browse your “power” pages
Your “power” pages are those with the most backlinks and authority. You can find these using the Best by links report in Ahrefs Site Explorer.
Site Explorer > enter your domain > Best by links
Looking down this list, you can often find relevant pages and posts from which to add links.
For example, our noob‐friendly link building guide is the eighth most authoritative page on our blog. That post happens to have a section on link building with images—something that I talk briefly about in our image SEO guide.
This is another perfectly relevant and useful place to add an internal link to that guide.
You can also use this method to direct some much‐needed authority to product and service pages.
For example, say that you sell protein powder online. You’d probably want your ecommerce category page to rank in Google for things like “buy protein powder.” These types of pages can be difficult to build links to.
But perhaps you have an authoritative blog post about protein powder or building muscle that you can add internal links from?
Those internal links will boost the “authority” of your ecommerce category page.
Internal linking isn’t rocket science. You simply need a logical, hierarchical site structure and for your internal links to follow that structure. That’s the basics, at least—you can then strategically link from your “power pages” to those that need a little SEO help.
Here are a few guidelines to follow when building any internal links:
- Don’t always use the same anchor text. Mix things up and keep it diverse.
- Don’t link from irrelevant pages only to boost authority. You’re better off not linking internally at all.
- Don’t overdo it. You don’t have to add hundreds of internal links for this to be effective—one or two well‐placed internal links can often make a big difference.
As I said, it’s far from rocket science. However, if you’re in any doubt as to what to do, here’s my advice: spend an hour or two browsing Wikipedia. Their internal linking game is on point, and there’s a lot you can learn from them—even if you only run a small website.