SERP Overlap & Similarity
SERP Overlap & Similarity is a free tool. It compares the Google results (SERPs) of your keywords and shows how much they overlap. The overlap tells you if two phrases should share one page or get separate pages. The bulk mode groups large keyword lists into clusters by how similar their results are.
What does the SERP Overlap & Similarity tool do?
Main keyword versus other keywords
You enter one main keyphrase and a list of phrases to compare it with. The tool fetches the top organic Google results for each phrase. Then it compares the ranking URLs. You choose how deep to compare, from the top 3 up to the top 50 results.
For every phrase you get a similarity percentage. A score of 100% means the results for both phrases are exactly the same. The higher the value, the more Google treats the phrases as the same search intent.
The tool always shows similarity for the top 3, top 5 and top 10. You can extend the comparison up to the top 50 results. You decide which depth drives the recommendation.
Create a new page or optimize an existing one
Each phrase receives a clear recommendation. When the similarity is at or above your threshold, the tool suggests optimizing the same page. Below the threshold, it suggests creating a new page. Sometimes two phrases are just the same words in a different order. For example "hotels paris" and "paris hotels". Here the tool keeps the single-page recommendation and labels them as a reorder. So you never split the same intent across competing pages.
This answers one of the most common SEO questions. Should this phrase get its own page? Or can one page rank for many similar phrases at once? Targeting one page for phrases that share a SERP also helps you avoid keyword cannibalization.
Bulk SERP similarity checker
The bulk mode compares every keyword on your list against every other keyword. It is built for large lists, for example keywords exported from the Keyword Ideas tool.
Phrases whose search results overlap above your threshold are grouped together. From each group the tool keeps a single representative keyword and lists the rest as similar keywords.
The representative is chosen by the highest search volume. If two phrases have the same volume, the tool picks the one that appears more often in the result titles. The final tie-break is the higher position on your list.
Search volume and a clean keyword list
In bulk mode the tool also pulls the Google search volume for each phrase. That is what lets it choose the strongest representative for every cluster.
The result is a de-duplicated keyword list. Instead of dozens of overlapping phrases, you get one strong phrase per topic plus its related variants.
Visualizations: Venn, URL comparison, matrix and rival domains
In the comparison mode the SERP overlap is shown as a Venn diagram. Next to it, a side-by-side URL comparison marks which ranking URLs are shared. It also marks which are unique to each phrase. Hovering a similarity score reveals the exact overlapping URLs.
In bulk mode you also get a similarity matrix. It is a heatmap of every keyword pair. You also get a top ranking domains panel. It shows which domains rank for the most of your keywords. It also shows their average position across those results. So you instantly see your real competitors.
Location and language support
You choose the country and language your queries relate to. The tool uses live, location-specific Google results, so the similarity reflects the market you actually target.
How does SERP Overlap & Similarity help SEO specialists and website owners?
The tool removes guesswork from content planning. Instead of manually opening Google for every phrase, you get the overlap calculated for you.
- Decide quickly whether to build one page or several for a group of similar phrases.
- Prevent keyword cannibalization by targeting one page per shared SERP.
- Turn a long, messy keyword list into a clean set of topics for articles.
- Feed the representative keywords into a content generator and the similar keywords into related keywords.
- Work with live, country-specific Google results, not cached guesses.
From clusters to content
The representative keywords from bulk mode make a ready list of topics for new articles. The similar keywords from each cluster are a perfect source of related phrases to include in your content.
That makes SERP Overlap & Similarity a natural first step before writing. First you map the topics. Then you create one strong page per topic, instead of competing pages.
Comparison of the SERP Overlap & Similarity tool with other tools
| Feature | DiagnoSEO | Other SERP overlap tools |
|---|---|---|
| SERP overlap for two keywords (Venn + shared URLs) | ✅ | ✅ |
| Cluster a whole keyword list (bulk mode) | ✅ | ❌ |
| Compare depth from top 3 up to top 50 | ✅ | ❌ (top 10 only) |
| Similarity matrix (every keyword pair) | ✅ | ❌ |
| Top ranking domains with average position | ✅ | ❌ |
| Search volume for each keyword | ✅ | ❌ |
| Live, country- and language-specific SERPs | ✅ | ⚠️ limited |
| Smart one-page-or-many recommendation (word-order aware) | ✅ | ⚠️ score only |
| CSV export of results | ✅ | ❌ |
| Part of a full SEO suite (content, related keywords) | ✅ | ❌ |
FAQ
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It measures the share of identical ranking URLs that two keywords have in the top results. The more URLs they share, the closer their search intent.
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When two keywords share results above your threshold, one page can rank for both. Below the threshold, separate pages usually work better.
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By the highest search volume. Ties are broken by how often the keyword appears in the result titles, then by its order on your list.
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You can compare the top 10, 20, 30, 40 or 50 organic results. Deeper checks cost one extra credit per keyword for each additional ten results.
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Yes. Every check fetches current, location-specific Google results, so the similarity reflects the market you target.