Topic clusters are a way of organizing a website so that each subject lives in one connected group of pages: one pillar page for the broad topic, several cluster pages for its sub-topics, and internal links that tie them together. They are one of the building blocks of an SEO content strategy, and this site is laid out in them.
People often mix clusters up with topical authority. The two are linked but not the same. A cluster is something you build. Topical authority is the standing you hope a well-built cluster earns over time. This page covers the build.
Where the topic cluster model comes from
The model was popularized by HubSpot. A Content Marketing Institute article from October 2018 says the topic cluster methodology, “also known as the ‘pillar-and-cluster’ technique, was first detailed by HubSpot Research in 2017.” It describes the model as creating content “around one central topic” called the pillar, with supporting posts that “explain sub-topics based on your pillar content and generate internal links to the pillar page.”
HubSpot rebuilt its own blog this way. Its post How We Used the Pillar-Cluster Model to Transform Our Blog says: “We reorganized our entire blog infrastructure according to the topic cluster model, which calls for the grouping of related blog posts around specific topics.” It contrasts that with “writing blog posts to try to rank for different long-tail keywords.”
The idea is older than the name. Sites have grouped related pages under section pages for as long as there have been sites. What the model added was a rule of thumb: plan pages by topic first, then by keyword, and link them on purpose.
The three parts of a topic cluster
Every cluster has the same three parts.
The pillar page
The pillar covers the broad subject at a high level and points to everything under it. HubSpot’s definition: “A pillar page covers the topic thoroughly and broadly, so a visitor could answer any basic questions about the topic.” It is the page you would send someone to if they asked you for an overview.
Cluster pages
Each cluster page takes one sub-topic and covers it properly. A good test is whether a reader who lands on it from search gets a complete answer without needing the pillar. If a sub-topic can be covered in a short section, it belongs on the pillar instead of on its own page.
Internal links
The links are what turn a pile of pages into a cluster. The pillar links down to each cluster page. Each cluster page links back up to the pillar. Cluster pages that touch each other link across. Without those links, you have related pages, not a cluster.
| Part | Its job | Example on this site | Links |
|---|---|---|---|
| Pillar page | Overview of the whole subject | What are Google SERP features? | Down to every cluster page |
| Cluster page | One sub-topic in full | What are featured snippets and how do you get one? | Up to the pillar, across to related cluster pages |
| Internal links | Show how the pages relate | The breadcrumb, sidebar and “Next to this box” list on every page here | Up, down and across |
Does Google rank topic clusters?
Google does not use the term. We found no Search Central page that mentions topic clusters when we searched on 5 November 2026. What Google does document are the two things a cluster is made of: a logical site structure and internal links.
On structure, Google’s SEO Starter Guide says organizing a site “in a logical way” can “help search engines and users understand how your pages relate to the rest of your site.” For larger sites it adds that “using directories (or folders) to group similar topics can help Google learn how often the URLs in individual directories change.” That second point is about crawling, and the guide frames it for sites with “more than a few thousand URLs.”
On links, the same guide says “the vast majority of the new pages Google finds every day are through links.” Google’s link best practices say “Every page you care about should have a link from at least one other page on your site,” and ask you to “link to those pages in context.” Its page on AI features and your website lists “making your content easily findable through internal links on your website” as one of the basics that still apply to AI Overviews and AI Mode.
So a cluster does not trigger any special treatment. It is a tidy way to do two things Google already asks for. Our reading is that this is the honest case for clusters: they help readers and crawlers find and connect your pages, and that is reason enough.
Topic clusters vs keyword clustering vs topical authority
Three similar names, three different jobs.
| What it is | What it decides | |
|---|---|---|
| Keyword clustering | Grouping search terms that share one answer | Which keywords one page should target |
| Topic clusters | Grouping pages around a subject, with links | Which pages a section needs and how they connect |
| Topical authority | The standing a well-covered subject earns | Nothing directly. It is the hoped-for result |
In practice, you do keyword clustering first, to work out what each page should cover, and then arrange those pages into a topic cluster.
How to build a topic cluster
1. Pick a subject broad enough for a pillar
A pillar topic should have several distinct sub-topics, each with its own questions. “SERP features” works: featured snippets, related searches and autocomplete are all separate subjects. “How to turn off People Also Ask” does not: it is one question.
2. Collect the questions
Search the subject and look at what people ask. Google’s People Also Ask box is a good start because it shows how questions nest: open one and Google adds more beneath it. PAA Box, our own free Chrome extension, opens the box up to four levels deep and exports each question with its parent question to CSV, which gives you a rough draft of the cluster’s shape. Add questions from your own customers, support inbox and keyword tool.
3. Sort questions into pages
Group questions that need the same answer. Then decide, group by group, whether it needs its own page or a section on the pillar. Our rule: if a group has follow-up questions of its own, or needs more than a few paragraphs, it gets a page. If not, it is a section.
4. Plan the URLs
Put cluster pages under the pillar’s folder where your site allows it, so the address shows the relationship. On this site, every SERP feature page sits under /serp-features/. This is a convenience for readers more than a ranking trick; Google’s directory advice above is aimed at crawling large sites.
5. Write the pillar last, or rewrite it last
A pillar is easier to write once you know what the cluster pages say. It should summarize each sub-topic in a sentence or two and link down to it, not repeat it. If the pillar covers a sub-topic in full, the cluster page has nothing left to add.
6. Link with descriptive text
Google’s link guidance says “Good anchor text is descriptive, reasonably concise, and relevant to the page that it’s on and to the page it links to.” Use the cluster page’s question or a natural phrase from it. Link up to the pillar early on each cluster page, so a reader who arrives from search can see where they are.
7. Fill the gaps
Once the cluster is live, compare it with what people search for and what other sites cover. A content gap analysis shows which cluster pages are missing, and each new page gets a content brief before anyone writes it.
How many pages should a topic cluster have?
As many as there are distinct questions worth a page, and no more. There is no target number. Google’s link guidance makes the same point about links: “There’s no magical ideal number of links a given page should contain.”
The risk runs the other way. Splitting one subject into dozens of thin pages to look complete is the pattern Google’s spam policies describe as scaled content abuse: “when many pages are generated for the primary purpose of manipulating search rankings and not helping users.” Its helpful content guidance asks whether your site has “a primary purpose or focus,” which a small, solid cluster shows better than a large, thin one.
How this site uses topic clusters
We build every section with a three-level version of the model that we call AKA: Authority, Knowledge and Answer. The Authority page is the pillar. Knowledge pages, like this one, are the cluster pages for the main sub-topics. Answer pages sit under them for specific questions that need a short page of their own. The extra level keeps narrow questions off the pillar without turning every one of them into a long guide. The method, and why we use it, is explained on our page about topical authority linked above.
For a worked example of turning a People Also Ask harvest into this kind of structure, see turning People Also Ask into a content plan.
Common mistakes
- A pillar that says everything. If the pillar covers each sub-topic in full, the cluster pages compete with it.
- Cluster pages with no way back. A cluster page that never links to its pillar leaves readers stranded and breaks the structure.
- One page per keyword variant. Two pages answering the same question split your effort. Merge them.
- Clusters that are too broad. “Marketing” is a site, not a cluster. Narrow it until the sub-topics are clear.
- Building it once and forgetting it. New questions appear. Check the subject every few months and add what is missing.