Staaarter

Keyword Cluster Generator

Pastes a list of keywords, one per line, and groups them into clusters based on how much their significant words literally overlap (a Jaccard-similarity heuristic, not semantic or ML-based clustering), suggesting the shortest keyword in each cluster as a head term for content planning. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-08-04
By Staaarter Team
generatorkeyword-researchcontent-planning

Overview

Introduction

A keyword research export often lands as a flat list of hundreds of phrases with no structure: figuring out which ones belong on the same page and which deserve their own page is normally a manual, tedious sorting exercise.

This tool automates the first, mechanical pass of that sorting by grouping keywords that share enough significant words, so you can review clusters instead of individual lines and decide where real content planning judgment is still needed.

What Is Keyword Cluster Generator?

A client-side keyword grouping tool that takes a newline-separated list of keyword phrases and clusters them by literal word overlap, using Jaccard similarity over each phrase's significant (non-stopword) words.

Each cluster comes with a suggested head term, the shortest keyword in that group, as a starting point for which phrase to treat as the page's primary target - though the final call on that is still yours.

How Keyword Cluster Generator Works

Every keyword line is lowercased and split into words, common stopwords ("the", "for", "best", and similar) are stripped out, and the remaining word set is compared pairwise against every other keyword's word set using Jaccard similarity (shared words divided by total unique words across both phrases).

Clustering is single-link and greedy: starting from the first unclustered keyword, every other keyword similar enough to it OR to any keyword already added to that cluster gets pulled in, then the next unclustered keyword starts a new cluster, and so on until every keyword belongs to some cluster (including clusters of one, for keywords with no close match).

When To Use Keyword Cluster Generator

Turning a raw keyword research export into a rough content outline, grouping variants that likely belong on the same page before deciding on final page structure.

Spotting near-duplicate keyword phrasings in a large list that are probably targeting the same search intent and don't need separate pages.

Features

Advantages

  • Runs entirely in the browser on a list of any size with no API, no rate limit, and no keyword data sent anywhere.
  • The three threshold levels let you quickly re-run the same list looser or stricter to see how grouping changes, without re-entering anything.
  • Duplicate keyword lines (case-insensitive) are automatically removed and reported, so an accidental copy-paste duplicate doesn't skew a cluster's size.

Limitations

  • This is a literal word-overlap heuristic, not semantic or ML-based clustering - it has no concept of synonyms, misspellings, or search intent, so related keywords that don't share words ("cheap flights" vs "budget airfare") will never cluster together.
  • It has no access to actual search volume, competition, or ranking data, so the suggested head term is a structural guess (the shortest phrase), not a data-informed recommendation - verify it against a real keyword research tool before committing to it.

Examples

A tight cluster at the Medium threshold

Input

best running shoes
running shoes for beginners
top running shoes 2026
running shoe reviews

Output

Cluster 1: running shoe reviews (4 keywords)
  - best running shoes
  - running shoe reviews
  - running shoes for beginners
  - top running shoes 2026

All four phrases share the words "running" and "shoe(s)", clearing the 40% overlap bar even though each also has unique words like "beginners" or "reviews".

Best Practices & Notes

Best Practices

  • Start with the Medium threshold and skim the results before switching to Loose or Strict, so you have a baseline for how the change affects cluster sizes.
  • Treat each cluster as a starting hypothesis for a content group, not a final content plan - manually check that keywords grouped together truly share the same search intent before merging them into one page.

Developer Notes

Clustering is O(n^2) in the number of keywords since every pair is compared once; fine for the hundreds-of-keywords lists this tool is meant for, but a list in the tens of thousands would visibly slow down as a synchronous main-thread computation, since there's no worker offload here.

Keyword Cluster Generator Use Cases

  • Turning a flat keyword research export into rough topic groups before building a content calendar
  • Auditing an existing site's target keywords for near-duplicate phrasings that might be causing keyword cannibalization
  • Quickly checking how tightly a list of keyword variants relates to each other before deciding whether they need separate landing pages

Common Mistakes

  • Assuming a cluster with only one keyword in it means that keyword has no related terms at all, when it may just mean no other keyword in this specific list happened to share enough words with it.
  • Treating the suggested head term as a final decision without checking real search volume - the shortest phrase in a cluster isn't always the one people actually search for most.

Tips

  • If most keywords end up as singleton clusters, try the Loose threshold; if unrelated keywords keep landing in the same cluster, try Strict.

References

Frequently Asked Questions