Building Topical Link Clusters That Hold Together
Most sites that publish regularly already have clusters of content on the same subject; they just do not behave like clusters. Ten articles about heat pumps sit in the blog, a service page about heat pump installation sits in the menu, and hardly any of them link to each other.
A topical link cluster fixes that by giving one page the job of overview, linking it to every detailed page on the subject, and linking those detailed pages back and across where it helps the reader. This guide shows how to find your existing clusters, map the links between them, and close the gaps.
What a cluster looks like in linking terms
A topic cluster is a small, deliberate network of pages about one subject. In link terms it has three rules:
- The pillar links down to every spoke. The pillar page gives the overview and, for each sub-topic, a short summary plus a link to the page that covers it properly.
- Every spoke links up to the pillar. Each detailed page links back to the overview in its introduction or conclusion, so a reader who arrives on a narrow page can find the wider picture.
- Spokes link across when it helps. A page on heat pump running costs naturally links to the page on grants and to the page on sizing, because readers of one need the others. Spokes do not need to link to every other spoke.
That shape does two jobs. For visitors, it turns a pile of articles into something they can explore in a sensible order. For search engines, it shows clearly which pages belong together, which page is the broad overview, and that the site covers the subject in depth rather than with one isolated page.
It is not a special markup or a plugin. It is ordinary links, placed with a plan. The planning behind which sub-topics to write about is covered by the Question Finder fixes; this guide is about linking the pages you have, or are about to publish, into a structure that holds together.
Signs your clusters are not working
The Internal Link Analysis maps every internal link across your crawled pages, measures click depth, and counts the links in and out of each page. Filter it down to the pages on one subject and look for these patterns.
| What you see | What it means |
|---|---|
| The page you think of as the overview has few incoming links from pages on the same topic | The spokes are not linking up. The overview looks no more central than any other page. |
| The overview page links out to only two or three of the ten related pages | The pillar is not doing its job of guiding readers through the subject. |
| Several topic pages have zero or one incoming link | They are near-orphans, found only through the blog archive or the sitemap. |
| Topic pages sit five or six clicks from the homepage | They are reachable only through paginated archives; the cluster has no route from the main navigation. |
| The strongest links into topic pages come from unrelated articles | Links were added for convenience rather than relevance, which blurs what belongs together. |
| Two pages receive links with near-identical anchor text | Pillar and spoke, or two spokes, may be competing for the same subject. |
Search Console can add a second view. If the performance report shows two of your pages swapping places for the same queries, that often points to an overlap inside a cluster, which the cannibalisation guide covers in detail.
Choosing the pillar page
The pillar is the page that answers "tell me about this subject" rather than one narrow question. Before writing anything new, check whether you already have a page that can take the role.
Good candidates
- A service or category page that already covers the subject broadly, such as "Heat pump installation" on a heating firm's site or "Walking boots" in a shop. Commercial pages make strong pillars when they include genuine explanatory content, not just a list of products.
- An existing broad guide that already attracts visits and links from other sites. Upgrading a page that is already trusted is usually better than starting from scratch.
- A new overview page, when nothing existing fits. Write it last, once you know which spokes exist, so its summaries point at real pages.
Poor candidates
- A tag or category archive that only lists post titles. It links to everything, but gives no overview, and its content changes every time you publish. It can support the cluster as a browse page, but a written pillar is more useful.
- The newest article on the subject, just because it is the longest. Length does not make a page an overview.
- The homepage. It should link to your main pillars, not act as one.
The link matrix: seeing the cluster on one screen
A link matrix is a simple grid in a spreadsheet. List every page in the cluster down the side as the source, and the same pages across the top as destinations. Put a 1 in a cell if the source page links to the destination page in its main content. Menu and footer links do not count here, because they are the same on every page.
| From \ To | Pillar: heat pumps | Running costs | Grants | Sizing | Noise |
|---|---|---|---|---|---|
| Pillar: heat pumps | – | 1 | 1 | ||
| Running costs | – | 1 | |||
| Grants | 1 | – | |||
| Sizing | – | ||||
| Noise | – |
The gaps jump out. The pillar does not link to sizing or noise. Only the grants page links up to the pillar. Sizing and noise have no links in or out within the cluster, so a reader who lands on either has nowhere topical to go.
Fill the grid from the per-page link data in the Internal Link Analysis, or by opening each page and checking its body links. For a cluster of ten to fifteen pages, doing this by hand takes less than an hour and is worth it, because you will see the whole structure at once.
What a finished matrix looks like
- The pillar's row has a 1 in every column.
- The pillar's column has a 1 in every row.
- Other cells are filled only where a reader of one page genuinely benefits from the other. Some rows will have two or three cross-links, others none. That is fine.
The fix, step by step
Step 1
List the pages that belong to one topic
Pick one subject that matters to your business and gather every page about it: service or category pages, blog posts, guides, FAQs and case studies. Use your site search, your CMS categories and the page list from the Internal Link Analysis. Include old posts you may have forgotten. Leave out pages that only mention the subject in passing. A workable cluster is usually between five and twenty pages; if you have far more, split the subject into two or three narrower clusters.
Step 2
Choose or create the pillar page
Decide which page will be the broad overview. Prefer an existing service, category or guide page that already gets visits and covers the subject widely. If none fits, plan a new overview page with a short summary of each sub-topic. If two pages both try to be the overview, merge them and redirect one. Write down the pillar's address at the top of your spreadsheet so everyone linking into the cluster uses the same page.
Step 3
Build the link matrix
In a spreadsheet, list the cluster pages down the side and across the top. For each page, mark which other cluster pages it links to from its main content, ignoring menus and footers. This link matrix shows at a glance where the pillar fails to link down, where spokes fail to link up, and which pages sit isolated inside their own topic. Colour the empty cells in the pillar's row and column, because those are the first links to add.
Step 4
Link the pillar to every spoke
Edit the pillar so each sub-topic has a short section, two or three sentences, that summarises the answer and links to the spoke page with anchor text naming that sub-topic. Add a section for any spoke the pillar does not yet mention. Avoid a bare list of links at the bottom; links placed inside the relevant explanation are more useful to readers and describe each destination better. Keep the pillar an overview rather than repeating every spoke in full.
Step 5
Link each spoke back and across
On every spoke, add one natural link to the pillar, usually in the introduction where the wider subject is mentioned, such as our guide to heat pumps. Then add cross-links only where a reader of this page would want the other one next, such as from running costs to grants. Two or three good cross-links per page are plenty. Do not add links to every sibling just to fill the matrix, because irrelevant links make each page harder to use.
Step 6
Remove overlaps between pillar and spokes
Read the pillar and each spoke side by side. If the pillar has grown a long section that duplicates a spoke, cut it back to a summary and link to the spoke. If two spokes answer the same question, merge them and redirect the weaker one to the stronger. Check anchor text too: the same phrase should not point at two different cluster pages. Each page should have one clear job that the others do not repeat.
Step 7
Re-run the analysis and review the cluster
After publishing the changes, run the Internal Link Analysis again. Check that the pillar is now among the most linked pages within the topic, that no cluster page has zero incoming links, and that click depth has fallen for pages that were buried in archives. Update the link matrix, then check Search Console over the following weeks for which cluster pages appear for which queries. Repeat the process for your next most important subject.
Patterns that make clusters easy to maintain
Contextual links in the body do most of the work, but a couple of small, consistent elements help readers and stop the cluster decaying as you add pages.
A short "part of" line on each spoke
A single sentence near the top of each spoke, linking to the pillar, is easy to add to a template or a reusable block:
<p class="cluster-note">
This article is part of our
<a href="/heat-pumps/">guide to heat pumps for UK homes</a>.
</p>A small topic menu at the end of each spoke
A short list of the other pages in the cluster, placed after the main content, gives readers a way on. Keep it to the cluster only, and to a handful of items; if the list grows beyond eight or ten, the cluster probably needs splitting.
<nav aria-label="More on heat pumps">
<h2>More on heat pumps</h2>
<ul>
<li><a href="/heat-pumps/running-costs/">What a heat pump costs to run</a></li>
<li><a href="/heat-pumps/grants/">Grants for heat pump installation</a></li>
<li><a href="/heat-pumps/sizing/">Sizing a heat pump for your home</a></li>
</ul>
</nav>This complements, but does not replace, links inside the text. A topic menu is identical wherever it appears, while a link placed in a relevant paragraph carries the context around it.
Do URLs need to match the cluster?
No. Folder-style addresses such as /heat-pumps/grants/ are tidy and help people understand
where they are, but links, not URL structure, are what connect a cluster. Do not change the addresses
of established pages just to group them; the redirects and lost history rarely justify it.
Platform notes
WordPress
Categories are a natural starting point for finding cluster pages, but a category archive is a list rather than an overview. A common pattern is to write the pillar as a normal page, link to it from the category archive's description, and use a reusable pattern for the "part of" line on each post. Related-posts plugins that choose by tag can support a cluster, but check that they pick pages from the same topic rather than simply the newest posts.
Shopify
For shops, a collection page is often the natural pillar, with buying guides and blog articles as spokes. Add a short written introduction to the collection with links to the guides, and link from each guide back to the collection and to specific products where relevant. Blog tags can group articles, but tag pages are thin lists and should not be treated as the pillar.
Custom and static sites
If your content lives in files, add a topic field to each page's front matter and generate
the topic menu from it at build time. That keeps the cluster list accurate as pages are added, while
you still write the contextual links by hand.
Edge cases
- A page that fits two clusters. Pick one home for it, link up to that pillar, and let the other pillar link to it as a related read. Forcing it into both clusters' menus usually makes both less clear.
- Small sites. A local business with twenty pages may have only two or three clusters, each with a service page as the pillar and three or four supporting pages. That is a perfectly good structure; there is no minimum size.
- Very large clusters. When a topic has forty pages, one pillar cannot summarise them all usefully. Create sub-pillars, such as "heat pump costs" and "heat pump installation", each with their own spokes, and link the main pillar to the sub-pillars.
- Old posts that no longer fit. Out-of-date articles should be updated, merged into a current spoke, or retired. Linking stale content into a fresh cluster weakens it.
- Clusters and link bloat. A cluster is not a reason to link every page to every other page. If a spoke links to fifteen siblings, it is behaving like a menu. Keep cross-links to those a reader would actually use.
1. What is the difference between a pillar page and a category page?
A category page, in most systems, is an automatically generated list of posts or products in that category. A pillar page is written: it explains the subject in overview, summarises each sub-topic and links to the pages that cover them in depth. A category page can become a pillar if you add genuine introductory content with contextual links, which works particularly well for shop collections, but a bare list of titles does not do the pillar's job.
2. How many pages should a topic cluster have?
There is no set number. A cluster needs enough spokes to cover the questions people actually ask about the subject, which might be four pages for a narrow local service and twenty for a broad product area. Once a pillar can no longer summarise every spoke in a few sentences each, split the topic into sub-pillars. A small, complete cluster is more useful than a large one padded with thin pages written just to fill it.
3. Should every page in a cluster link to every other page?
No. The essential links are from the pillar to every spoke and from every spoke back to the pillar. Links between spokes should appear only where a reader of one page genuinely needs the other next, such as running costs linking to grants. Linking every page to every sibling turns each page into a menu, adds noise and makes the important links less meaningful. Two or three well-chosen cross-links per spoke is usually plenty.
4. Do I need a special plugin to build topic clusters?
No. A cluster is made of ordinary links placed with a plan, and you can build one in any CMS using the normal editor. A spreadsheet link matrix is the most useful tool for planning and checking it. Plugins that list related posts or insert links automatically can help with upkeep, but check what they produce, because automated choices are often based on recency or shared tags rather than whether the pages actually belong together.
5. Will building clusters improve my rankings?
Clusters help search engines understand which of your pages belong together and which one is the overview, and they help visitors find the depth you already have. That can support better visibility for the subject as a whole, but there is no guaranteed effect, and the content itself still has to be useful. The most reliable gain is practical: fewer isolated pages, shorter click paths and a clear place for new articles on the topic to link into.
6. What if my pillar and a spoke compete for the same searches?
That usually means the pillar has grown to cover the spoke's subject in full, or the two pages were written to answer the same question. Cut the pillar's section back to a short summary with a link to the spoke, so each has a distinct job. If the two pages are genuinely duplicates, merge them into the stronger one and redirect the other. Also check that you are not using the same anchor text for links to both pages.
7. Should I change my URLs so each cluster sits in its own folder?
Not for established pages. Folder-style addresses are tidy for new content and help people see where they are, but it is the links between pages that make a cluster work. Moving existing pages means redirects, updating every internal link and some temporary disruption, which is rarely worth it. Use folders for new clusters if you like, and connect your older pages to them with contextual links rather than with new addresses.
The Internal Link Analysis maps every internal link across your crawled pages, measures click depth and counts links in and out of each page, so you can see whether a topic cluster is actually connected.
Open Internal Linking Fixes →