Keyword clustering

What is keyword clustering?

Keyword clustering is grouping related keywords that share the same search intent and similar Google results, so each group can be targeted by one page. For example, "how to descale a kettle", "kettle descaling vinegar" and "remove limescale from kettle" form one cluster. Clustering turns a long keyword list into a list of pages to create.

The most reliable method is SERP overlap: if two keywords share several of the same URLs in their top 10, Google treats them as one topic, so one page can rank for both. Grouping by shared words alone is less reliable, because "apple pie" and "apple support" share a word but nothing else. Many tools automate SERP-based clustering; you can also do it by hand for smaller lists.

Why keyword clustering matters for SEO

Without clustering, it is easy to write a separate page for every keyword variation, which creates thin, overlapping pages and keyword cannibalization. Clustering gives you fewer, stronger pages that each rank for many queries.

Clusters also make planning easier. Each cluster has a primary keyword and secondary keywords, and related clusters can be organised into a topic cluster with a pillar page and supporting pages.

How to cluster keywords

1. Export your keyword list with volume and intent.
2. Pick the highest-volume keyword not yet grouped and look at its top 10.
3. For each remaining keyword, compare its top 10. If they share around three or more URLs, put it in the same cluster.
4. Split keywords with different intent into separate clusters even if the wording is similar.
5. Name each cluster by its primary keyword and sum its volume.
6. Repeat until every keyword is grouped, then map clusters to pages.

Keyword clustering example

Cluster: how to descale a kettle
  how to descale a kettle
  descale kettle with vinegar
  kettle limescale removal

Cluster: best kettle for hard water
  best kettle for hard water
  kettle with limescale filter