What is Internal and External Linking in SEO? A Complete Breakdown

Most websites have links — but few have a deliberate linking strategy. Internal and external links are present on virtually every page across the web, yet the logic behind how they should be placed, what they should say, and where they should point is often left entirely to chance. That gap between having links and using them well is where significant ranking opportunity tends to sit.

This article covers what internal and external linking in SEO actually means, how each type works, and what you should be doing about both — starting this week.

If you're looking for expert help in this area, explore how Indexed's programmatic SEO services can drive measurable results for your business.

What is Internal and External Linking in SEO?

The question "what is internal and external linking in SEO?" comes up often — and the answer is more nuanced than most introductory resources suggest.

Internal links are hyperlinks that connect one page on your website to another page on the same domain. They help users navigate between related content and allow search engines to discover and understand the relationship between your pages. When Google crawls your site, it follows internal links to map out your content architecture and decide which pages deserve crawl priority.

External links encompass two distinct relationships. First, outbound external links: hyperlinks from your pages pointing to content on a different domain. Second, inbound external links — commonly called backlinks — which are links from other websites pointing to yours. Both directions carry SEO implications, but they work very differently.

Why Anchor Text Matters for Both Types

The visible, clickable text of any link — the anchor text — gives search engines contextual signals about what the destination page covers. Descriptive anchor text such as "topical authority building" communicates far more than "click here" ever could. This applies to internal links, outbound links, and the backlinks you earn from other sites. When anchor text is vague or repetitive across your site, you leave meaningful context on the table.

How Internal Links Shape Your Site's Architecture

Think of your website as a building. Internal links are the corridors that connect rooms. If a visitor — or a search engine crawler — can only reach certain rooms by walking through seven others, the architecture is inefficient. Pages that are difficult to reach through internal links tend to receive less crawl attention and accumulate less PageRank, Google's internal measure of page importance.

PageRank and Link Equity Distribution

PageRank flows through internal links. A high-authority page — one with strong backlink profiles or significant traffic — passes some of that authority to the pages it links to. This means strategic internal linking allows you to deliberately direct equity towards pages you want to rank. If you publish a new service page and link to it prominently from three high-traffic blog posts, you accelerate its authority accumulation in a way that simply publishing the page alone never would.

The practical implication: audit your highest-traffic and highest-authority pages. Are they linking to the pages you most want to rank? If not, that is one of the highest-return edits you can make without writing a single word of new content.

Crawl Depth and Orphan Pages

Pages more than three or four clicks from the homepage are often crawled infrequently — or missed entirely on smaller crawl budgets. Orphan pages — those with no internal links pointing to them — may not be crawled at all, regardless of how strong the content is. A quarterly internal link audit using tools such as Semrush's site audit or Screaming Frog will surface orphan pages and over-deep content before they become ranking dead zones.

Outbound External Links: The Credibility Signal Most Sites Ignore

Linking out to other websites makes many site owners uneasy. The instinct is to keep users on your pages — but that instinct works against you in certain respects. Search engines interpret outbound links to authoritative, relevant sources as a quality signal. A page that cites a primary source from Google's own documentation or a peer-reviewed study demonstrates editorial rigour. A page that references claims without any supporting links looks, to both users and algorithms, less trustworthy.

This is the angle most competitor articles on this topic skip entirely: outbound linking is not just neutral — used well, it is a positive trust signal. The key qualifiers are relevance and authority. Linking to a marginal or low-quality source does not confer the same benefit. Linking to the original study, the official documentation, or the authoritative trade body does.

When to Use rel="nofollow" or rel="sponsored"

Google introduced link relationship attributes to help publishers signal the nature of external links. rel="nofollow" instructs Google not to pass PageRank through the link and to treat it as a hint rather than an endorsement. rel="sponsored" should be applied to paid or affiliate links. rel="ugc" applies to user-generated content such as comments or forum posts. For standard editorial outbound links — where you are genuinely recommending a source — no attribute is needed, and adding nofollow unnecessarily signals editorial uncertainty rather than caution.

Inbound External Links (Backlinks): What Actually Builds Authority

Backlinks remain one of the strongest ranking signals in Google's algorithm. When an external site links to your content, it passes a vote of relevance and authority. Not all votes carry equal weight — a link from a well-established industry publication is worth substantially more than a link from a newly registered domain with no audience.

The quality markers that distinguish a valuable backlink from a negligible one include: the linking site's own authority, topical relevance to your content, placement within the body of an article rather than a sidebar or footer, and the descriptiveness of the anchor text used.

How Linking Behaviour Affects Backlink Acquisition

Here is a connection that rarely appears in beginner guides: your outbound linking behaviour influences the quality of backlinks you attract. Sites that consistently cite primary sources, reference original research, and link to authoritative external content tend to attract links from similar-quality publishers. Editorial standards are visible. A resource page at a university or a trade publication is far more likely to cite a page that itself demonstrates rigorous sourcing than one padded with generic claims and no references.

Building a backlink profile is therefore not purely an outreach exercise — it is partly a function of the editorial standard your content demonstrates.

The Linking Mistakes That Cost Rankings — and Are Easy to Fix

Most linking errors are not dramatic. They accumulate quietly across a site and compound over time. The most common ones we encounter in audits at Indexed include:

• Generic anchor text on internal links — using "read more" or "here" instead of descriptive phrases that tell search engines what the destination page covers.
• Linking to the homepage from within body content — the homepage typically needs no additional internal link support; that equity is better directed to deeper pages.
• Broken internal links — pages that have been moved or deleted leave orphaned link paths that waste crawl budget and frustrate users.
• Over-reliance on navigation links — if the only internal links to a page are in the header or footer, Google may not treat those links as meaningful editorial endorsements.
• No outbound links at all — a page that makes factual claims with zero supporting references reads as lower quality to both users and crawlers.
• Excessive outbound links to low-quality sites — linking out indiscriminately can associate your content with low-quality neighbourhoods of the web.

FAQ

Do internal links directly affect my Google rankings?

Yes — internal links influence rankings in two ways. They affect how search engine crawlers discover and prioritise your pages, and they distribute PageRank (link equity) across your site. Pages that receive more internal links from high-authority pages tend to rank better, all else being equal. This is why internal link audits often surface quick wins for existing content without requiring new pages to be created.

How many internal links should a page have?

There is no fixed ideal number. Google has historically recommended keeping the number of links on a page to a reasonable amount, but "reasonable" is contextual. A long-form guide might naturally contain 20–30 internal links without appearing spammy. A short news article might have five. The guiding principle is editorial relevance: link where the destination page genuinely adds value for the reader, not to hit a count.

Should I link out to competitor websites?

If a competitor's page is the most authoritative source for a specific claim, linking to it is editorially correct and reflects well on your content's quality. In practice, you will rarely need to link directly to a competitor's commercial pages — but linking to their published research, data studies, or informational resources is entirely appropriate and signals editorial confidence rather than weakness.

What is the difference between a backlink and an external link?

An external link is any hyperlink that points to a different domain. The term can apply to links you place on your site (outbound external links) or links from other sites pointing to yours (inbound external links). "Backlink" specifically refers to the inbound variety — a link from another website pointing to your content. In SEO discussions, "backlinks" and "inbound links" are used interchangeably, while "external links" often refers to outbound links in context.

What to Do This Week

Understanding the theory is the easy part. Here are the specific actions worth prioritising right now:

• Run a crawl audit. Use Screaming Frog (free up to 500 URLs) or a similar tool to identify orphan pages, broken internal links, and pages with no internal links pointing to them. Fix the broken links and add at least one contextual internal link to each orphan page.
• Audit anchor text on your top five pages. Open each page and count how many internal links use generic anchor text. Rewrite those anchors to describe the destination page's topic in two to four words.
• Identify your three highest-traffic pages. Check whether they link to the pages you most want to rank. If not, add a contextual internal link to each — within the body copy, not a sidebar widget.
• Review outbound links on your most-linked content. Ensure every factual claim that can be supported by a primary source has an outbound link to that source. Remove or replace any outbound links to low-quality or irrelevant domains.
• Document your linking rules. Write a one-page internal linking guide for your content team or contributors specifying anchor text standards, which pages are linking priorities, and your outbound link policy. Inconsistency across a team produces inconsistent site architecture over time.

Related Reading

• Paid vs Editorial Backlinks: What Builds Authority
• What Makes a High-Quality Backlink? (And What to Avoid)
• What Is Topical Authority and How Do You Build It?
• Content SEO: How to Create Content That Ranks, Converts and Gets Cited by AI
• Why Does SEO Still Matter in 2026?