Free website course · Lesson 12 of 21

Topic Clusters: How to Plan Your Site’s Content With Claude and Semrush (or Ahrefs)

By Eugene Madondo, SEO specialist · Rank to Earn · Updated November 2026

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After the last two lessons you probably have a long list of keywords. A list isn’t a plan. Topic clusters turn that list into a site structure: a handful of main topics, each with one pillar page and a group of supporting posts that link to each other. It’s how you show Google (and AI search tools) that your site covers a subject properly, and Claude can do the grouping in minutes.

The short answer

A topic cluster is one pillar page covering a broad topic, plus several supporting posts on narrower subtopics, all linked together. To build them, export your keywords from Semrush or Ahrefs, ask Claude to group them by search intent, check the groups against Google’s results, pick one pillar per group, and map the internal links before you write.

Key takeaways

Each cluster is one pillar page plus supporting posts (spokes) that link back to it and to each other.
Keywords belong in the same post when Google shows mostly the same pages for them. Otherwise they need separate posts.
Claude is fast at grouping; the SERP check is what makes the groups correct.
Start with two or three clusters you can finish, not ten you start.
This course is itself a topic cluster: the overview page is the pillar and every lesson is a spoke.

What a topic cluster is

A topic cluster is a group of pages about one subject. The pillar page targets the broad keyword and gives an overview. The spokes each target a narrower keyword and go deep on one part of it. Every spoke links to the pillar, the pillar links to every spoke, and related spokes link to each other.

Pillar page

Broad topic, e.g. “AI video editors”. Summarises each subtopic in a few lines and links to the full post.

Spokes

Narrow topics, e.g. “best AI video editor for YouTube”, “AI video editor free”, “how to add captions with AI”.

Why it works: a new site with a few complete clusters looks like an authority on those topics, rather than a scattering of unrelated posts. Internal links also pass authority from the posts that earn backlinks to the ones that don’t.

Step 1: Export your keywords

Start with the low-competition keywords you found in lesson 10. In Semrush, use the Keyword Magic Tool; in Ahrefs, use Keywords Explorer’s matching terms report. Export the keyword, search volume, keyword difficulty and, in Ahrefs, the parent topic. If you connected your tool to Claude in lesson 11, you can skip the export and ask Claude to pull the list directly.

Aim for 100 to 500 keywords around one seed topic. Fewer than that and there isn’t much to cluster; far more and the groups get messy.

Step 2: Cluster them with Claude

Paste or attach the export and use this prompt. Replace the capitalised parts.

Here is a keyword list for a new site about NICHE, with volume, keyword difficulty and parent topic. PASTE YOUR KEYWORD LIST HERE Group these keywords into topic clusters. – Keywords with the same search intent that one page could answer go in the same group. Name each group after its main keyword. – Put groups that belong to the same broad subject under one cluster, and suggest a pillar page for each cluster. – For each group show: main keyword, other keywords, total volume, average KD, and the intent (informational, commercial, transactional). – Flag any keyword you’re unsure about. Show the result as a table per cluster.

With a connector you can go further: “Using Ahrefs, pull matching terms for SEED KEYWORD with KD under 20, then cluster them as above.”

Step 3: Check the groups against Google

Claude groups by meaning. Google groups by results. Two keywords that sound the same can need different pages, and two that sound different can be answered by one. The test:

Search both keywords (or ask Claude to pull the SERP for each with your connector).
If several of the top 10 URLs are the same, keep them in one post.
If the results are mostly different, split them into separate posts.
Use Ahrefs’ parent topic as a shortcut: keywords that share a parent topic usually belong together.

Step 4: Choose pillars and spokes

Pick the pillar: usually the broadest keyword with the highest volume in the cluster. If its difficulty is too high for now, still make it the pillar; it ranks later as the spokes gain links.
Pick the spokes: every other group becomes one post.
Put money pages in the plan: reviews and “best X for Y” posts where your affiliate links go. Informational spokes link to them.
Cut what doesn’t fit: keywords with no clear home can wait for a later cluster.

Step 5: Map your internal links

Plan links before you write so you never publish an orphan page. Ask Claude:

Using the clusters above, build an internal-link map. For each post list: which pages it should link to, the anchor text to use (natural, varied, not exact-match every time), and which pages should link to it. Every spoke must link to its pillar, and the pillar must link to every spoke.

Tip: keep the map in a spreadsheet with columns for URL, cluster, status and “links to”. When you publish a new post, go back and add links to it from the older posts in the same cluster.

This course as a live example

You’re reading a spoke in a topic cluster right now. The free website course overview is the pillar. Each lesson targets its own keyword (this one: “topic clusters”), links back to the overview, and links to the lessons before and after it, plus related lessons such as how to get backlinks. The course sidebar is the internal-link map made visible.

Step 6: Turn it into a content calendar

Order the posts so each cluster gets finished quickly:

Write the easiest spokes first (lowest KD) so you start getting impressions.
Publish the pillar once three or four spokes are live, so it has pages to link to.
Finish one cluster before starting the next.
Set a pace you can keep, such as two posts a week.

Ask Claude: “Turn these clusters into a 12-week content calendar at two posts a week, easiest spokes first, pillar in week 3.”

Do this now

Export 100 to 500 keywords around your main topic.
Run the clustering prompt in Claude.
SERP-check the five groups you’re least sure about.
Choose your first cluster, its pillar and spokes, and build the link map.

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Summary: topic clusters

A topic cluster is a pillar page on a broad topic plus supporting posts on narrower subtopics, all linked together. Export 100 to 500 keywords from Semrush or Ahrefs, have Claude group them by intent, confirm the groups by checking whether Google shows the same pages, choose a pillar and spokes, map the internal links, and publish the easiest spokes first so each cluster gets finished.

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Frequently asked questions

What is a topic cluster in SEO?

A topic cluster is a group of linked pages about one subject: a pillar page that covers the broad topic and several supporting posts that each go deep on a narrower subtopic. The links between them help search engines understand that your site covers the subject thoroughly.

How many posts should a topic cluster have?

There’s no fixed number. Many clusters have one pillar and somewhere between five and fifteen supporting posts. Cover the subtopics people actually search for, and stop when the remaining keywords have no real search demand.

Can Claude cluster keywords?

Yes. Paste or attach your keyword export and ask Claude to group keywords by search intent. It’s fast and usually close, but check uncertain groups by searching the keywords and seeing whether Google shows the same pages.

Should two keywords go in one post or two?

Search both. If several of the top 10 results are the same pages, one post can rank for both. If the results are mostly different, write separate posts.

Do I need Semrush or Ahrefs to build topic clusters?

They make it faster because they give you volume, difficulty and parent topics. You can start with free tools such as Google autocomplete and Search Console, or use a free trial of a paid tool to pull your list once.

About Eugene Madondo

Eugene is a Cape Town-based SEO specialist and digital entrepreneur who has been earning online since 2012. He has worked in SEO at a tech startup, an agency and in-house tech roles, ran a consulting business, and has generated over $1.4 million from his own affiliate websites since 2020. He teaches website operators through Rank to Earn.

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