What are topic clusters?
A topic cluster is a way of organizing content around one subject. A broad pillar page gives an overview of the topic and links out to cluster pages, each covering one subtopic in depth. Every cluster page links back to the pillar, and to other cluster pages where it helps the reader.
The structure makes a site easier to navigate for people and easier to understand for crawlers. It shows which page is the main entry point for a topic, which pages answer the detailed questions, and how they relate. It is one of the most practical ways to build topical authority.
How a cluster is structured
| Part | Purpose | Example (home espresso) |
|---|---|---|
| Pillar page | Overview of the whole topic, targets the broad query | "Home espresso: the complete guide" |
| Cluster pages | One subtopic each, target specific queries | "Espresso grind size", "How to steam milk", "Descaling an espresso machine" |
| Links | Pillar to every cluster page, each cluster page back to the pillar, related cluster pages to each other | "Grind size" links to "Dialing in a shot" |
The pillar summarizes each subtopic in a paragraph or two and links to the detailed page. It should not try to contain everything, or it competes with its own cluster pages.
How to plan one
- Pick the core topic and confirm it has a broad query people search.
- List subtopics from keyword research, People Also Ask, and questions customers ask you. Group keywords that share the same search intent into one page.
- Audit what you have. Existing posts often cover half the cluster already. Update and link them rather than writing duplicates.
- Write the missing pages, then the pillar last, once you know what it needs to point to.
- Link with descriptive anchors. "espresso grind size chart" says more than "click here". See anchor text.
In WordPress
WordPress categories can mirror clusters, with the pillar as a page and cluster posts in a matching category, but a category archive is not a substitute for a written pillar page. Breadcrumbs help show the hierarchy; see adding breadcrumbs. Hydrogen SEO's site audit flags orphan pages and keyword cannibalization, the two most common ways clusters break: a cluster page nobody links to, or two pages competing for the same query. The orphan pages guide walks through fixing the first.
Common mistakes
- Clusters that overlap. Two cluster pages targeting "espresso grind size" and "best grind for espresso" usually split one intent. Merge them; see fixing cannibalization.
- Pillars that are just link lists with no real overview.
- One-way linking, where the pillar links out but cluster pages never link back.
- Forcing every post into a cluster. Some posts stand alone, and that is fine.
Common questions
How many pages should a topic cluster have?
As many as there are distinct subtopics worth a page. Small clusters of five to ten pages are common, but the right number depends on how many separate questions the topic contains.
Is a pillar page the same as a category page?
Not usually. A category archive lists posts automatically. A pillar page is written content that explains the topic and links to cluster pages deliberately.
Do topic clusters help with AI search?
They can. AI search features split questions into sub-queries, and a cluster gives each sub-question a clear, well-linked page to be found.