Clustering without a subscription
Grouping keywords helps decide which searches one page can answer and which need their own page, and, for paid search, how to build tightly themed ad groups.
This grouper works in a transparent, repeatable way:
- Each keyword is split into words; common words are ignored.
- Words are reduced to their stem with the Porter stemming algorithm, so count, counter, counting share a stem.
- Every keyword is assigned to its most frequent stem across the whole list (or its most frequent two-word phrase, in phrase mode).
- Groups smaller than the minimum size go to “Ungrouped”.
The result is deterministic: the same list always gives the same groups, which makes it easy to iterate.
Limits of text-based grouping
Grouping by shared words can’t know that “word counter” and “character count tool” serve the same intent, or that “apple pie” and “apple phone” don’t. SERP-based clustering, used by commercial tools, compares which pages rank for each keyword and catches those cases (at the cost of paid API calls). Use this grouper for a fast first pass, then merge or split groups by hand.
Worked example
Here is what the Keyword Grouper returns for its built-in example. Settings used: Group by: Shared word. Click Try an example in the tool above to load it, then change it as you like.
word counter
free word counter
word counter for essays
character counter
character count tool
count characters online
title case converter
apa title case
title capitalization tool
case converter
sentence case converter| Result | Value |
|---|---|
| Keywords | 11 |
| Groups | 4 |
| Ungrouped | 0 |
Questions
How does keyword clustering work?
Here, keywords are grouped by their most common shared word stem (or two-word phrase). Commercial tools often compare search results instead.
Can I export the groups?
Yes. Download gives a CSV with the group name and keyword on each row.
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