On-Page SEO

Keyword Clustering

Shahid Maqbool

By Shahid Maqbool
On Jul 4, 2023

Keyword Clustering

What is Keyword Clustering?

Keyword clustering is a process in search engine optimization where related keywords are grouped together based on their semantic similarity. 

This technique involves analyzing a large set of keywords and identifying groups of terms that are related to each other in terms of meaning and intent.

Keyword clustering helps to organize and prioritize keywords for content creation and optimization.

By grouping related keywords together, it is easier to identify content gaps and opportunities for optimization.

This approach also helps to ensure that the content created for each group of keywords is more focused and relevant to the intended audience. 

Ultimately, keyword clustering can improve the effectiveness of SEO efforts by helping to drive more targeted traffic to a website.


Here's an example of how keyword clustering might work in practice:

Let's say that you are optimizing a website for a company that sells athletic shoes. You start by analyzing a large set of keywords related to athletic shoes and identify the following clusters using a semantic clustering approach:

Cluster 1: Running shoes, jogging shoes, trail running shoes, marathon shoes

Cluster 2: Basketball shoes, high-top shoes, low-top shoes

Cluster 3: Tennis shoes, court shoes, volleyball shoes, squash shoes

Cluster 4: Cross-training shoes, gym shoes, fitness shoes

Based on this clustering, you could then create content that targets each cluster specifically, using the most relevant keywords from each group.

For example, you might create a blog post about the best trail running shoes for marathons, or a product page featuring the latest high-top basketball shoes.

By grouping related keywords together, keyword clustering can help to ensure that your content is more focused and relevant to the intended audience. 

Why is keyword clustering important?

Keyword clustering is important in SEO for several reasons:

Better organization

Grouping related keywords together makes it easier to organize and manage large keyword lists.

This helps to identify content gaps and opportunities for optimization, which can save time and resources.

Improved relevance

Keyword clustering ensures that content created for each group of keywords is more focused and relevant to the intended audience. This can improve engagement metrics such as bounce rate, time on page, and conversions.

Enhanced targeting

By understanding the semantic relationships between keywords, it is easier to identify user intent and create content that addresses specific needs and queries. This can help to drive more targeted traffic to a website.

Competitive advantage

Keyword clustering can provide insights into how competitors are targeting specific keywords and topics.

By identifying gaps in their content strategy, businesses can create content that fills those gaps and provides a competitive advantage.

Types of keyword clustering

Here are some of the most common types of keyword clustering:

Hard clustering

In hard keyword clustering, the primary focus is on the search engine results that each keyword produces.

The idea is that if you search for two different keywords and they both produce largely the same top results (like the same web pages or websites appearing in the top 10 results), then these keywords are considered to be similar or related. These related keywords are then grouped, or "clustered," together.

This technique is beneficial for understanding how search engines relate different keywords and can help guide SEO strategy.

For instance, if you know that certain keywords produce similar search results, you can optimize a webpage to target all those similar keywords together, rather than creating separate content for each keyword.

Moderate clustering

Moderate keyword clustering is a strategy used in Search Engine Optimization (SEO) where keywords are grouped together not just based on the similarity of the search engine results they generate, but also based on how related or similar these keywords are to each other.

It is a more comprehensive method of grouping keywords. It not only looks at whether different keywords generate similar search results but also whether the keywords in a group generate similar results compared to each other.

This strategy can provide a deeper understanding of how keywords relate to each other, which can be helpful in optimizing content for search engines.

Soft clustering

This is the simplest method. It groups keywords based on the overlap of their search results. If two or more keywords generate similar top search results, they are clustered together.

However, this method doesn't look at the relationships between all the keywords in the cluster, it just compares each keyword to the main keyword.

Lemma-based clustering

This technique involves grouping together keywords based on their shared root word or lemma.

For example, words like "running," "runner," and "runs" would all be grouped together under the lemma "run." 

This technique can be useful for identifying semantic relationships between keywords that may not be immediately apparent and can help to optimize content for a wider range of search queries.

Is keyword clustering a positive signal for search engines?

Yes, search engines view keyword clustering as a positive signal for website organization and content relevance.

By grouping related keywords together, keyword clustering helps search engines to identify semantic relationships between different pieces of content on a website and to understand the overall theme and structure of the website.

When search engines recognize a website as having high-quality, relevant content that is well-organized and easy to navigate, they are more likely to rank that website higher in search results.

This can lead to increased visibility, traffic, and ultimately, conversions for the website.

Moreover, by using keyword clustering to optimize content for a wider range of search queries, websites can become recognized as a trusted authority in their niche or industry.

This can lead to improved visibility and rankings across a broader range of search terms and can help to establish a website as a go-to resource for users searching for information or solutions related to that niche.

Manual vs automated clustering

Keyword clustering is an important process in search engine optimization, as it helps to organize and optimize content for a wider range of search queries. 

There are two main approaches to keyword clustering: manual clustering and automated clustering

Here are some of the pros and cons of each approach:

Manual Keyword Clustering

This is a hands-on approach where keywords are grouped together based on human judgment and analysis of the search results.


  • Provides greater control over the clustering process

  • Allows for more nuanced and customized grouping of keywords

  • Can take into account factors like user intent and industry-specific terminology


  • Can be time-consuming and labour-intensive

  • May be prone to errors or inconsistencies

  • May be limited by the knowledge and expertise of the individual doing the clustering

Automated Keyword Clustering

This is a method where a tool or software is used to group keywords based on predetermined criteria, such as similarity in search engine results - enabling faster and more consistent analysis


  • Can save time and effort in the clustering process

  • Can analyze large amounts of data quickly and efficiently

  • Can use advanced algorithms to identify relationships and patterns that may be difficult to detect manually


  • May be less accurate or nuanced than manual clustering

  • May not take into account factors like user intent or industry-specific terminology

  • May require significant technical expertise to implement effectively

Keyword clustering and multiple keyword targeting

In the past, the focus of SEO was on assigning only two to three keywords per piece of content.

However, the focus has shifted to targeting user intent rather than keywords. This is where keyword clustering comes into play. 

When you group keywords into clusters, you can put related keywords together and write content that targets intent more naturally. 

The idea of creating clusters is based on how people search for and consume information online.

Since people have different reasons for looking for information online, these clusters of topics allow you to cover all the bases.

When assigning multiple keywords to a single piece of content, it's important to ensure that they are closely related to each other. 

For example, using keywords like "digital marketing," "digital marketing tips," "digital content marketing," "digital marketing tools," and "online marketing for beginners" together in a single piece of content can help to rank for multiple keywords. 

By doing this, you can create more opportunities to be found in search engine results. 

How to do clustering?

When it comes to creating an effective content strategy for your website, one of the most important things to consider is topic clustering. 

Here's a step-by-step guide to creating topic clusters:

Build keyword list

Start by brainstorming a list of keywords related to your business or niche. This can include broad topics as well as more specific long-tail keywords

When creating a keyword list, it's important to start with broad topics related to your business or niche.

This will help you identify the main themes you want to target and guide you in selecting more specific keywords to use.

For generating keyword ideas, there are several tools you can use. Google Keyword Planner is a popular option that provides insights into search volumes and helps identify related keywords.

Another tool that can be helpful is SEMrush, which offers a range of features including keyword research and competitor analysis.

When using these tools, start by entering a broad keyword related to your business or niche. 

For example, if you run a fitness blog, you might start with a keyword like "fitness". These tools will then provide you with a list of related keywords and their search volumes.

From there, you can start to identify more specific long-tail keywords that will be easier to rank for and help you target specific topics or themes. 

For example, you might identify "yoga for beginners" or "strength training for women" as more specific long-tail keywords to use.

Divide them into groups

Once you have a list of keywords, group them into clusters of related keywords based on topics and subtopics. 

This will help you to create a more targeted and strategic content plan. For example, if you run a marketing agency, you might have clusters for social media marketing, email marketing, content marketing, and so on.

Segmenting your keyword list into groups is an important step in creating effective topic clusters.

It helps you to identify and organize your content into different themes and topics, making it easier for your audience to navigate and find what they are looking for.

For segmenting your keyword list, start by looking for common themes and topics that are related to your business or niche.

This can include general topics like industry trends, as well as more specific subtopics like product features or customer pain points.

Once you have identified these themes and topics, group your keywords together based on their relevance to each other. 

For example, if you have keywords like "social media marketing strategy", "social media content creation", and "social media advertising", you can group them together into a cluster for "social media marketing".

By segmenting your keywords into groups, you can create a more organized and focused content plan that addresses specific topics and subtopics within your niche. 

Develop pillar pages for clusters

Create pillar pages that serve as the main hub for each of your keyword clusters. These pages should be optimized for the primary keyword of each cluster and link out to related subtopic pages. 

For example, your social media marketing pillar page might cover topics like Facebook marketing, Instagram marketing, and Twitter marketing, with internal links to dedicated pages for each topic.

This will help to reinforce the cluster's relevance and signal to search engines that your content is authoritative and informative.

The key is to ensure that your pillar pages provide high-quality, valuable content to your audience. 

You should also ensure that they are easy to navigate, visually appealing, and optimized for search engines. 

Reinforce clusters with blog content

Create blog posts that cover subtopics related to each of your keyword clusters. These posts should link back to the pillar page of the respective cluster, reinforcing the overall topic authority. 

For example, you might create blog posts on "10 Tips for Effective Facebook Marketing" or "The Ultimate Guide to Instagram Hashtags" that link back to your social media marketing pillar page.

Creating blog content not only reinforces the overall topic authority of your website but also provides an opportunity to target long-tail keywords that may not be suitable for a pillar page. 

When creating blog content, it is important to focus on quality rather than quantity. 

Remember to regularly update and optimize your content to ensure that it remains relevant and valuable to your audience. 

Keyword clustering tools

Keyword clustering tools are essential in helping businesses and marketers identify clusters of related keywords that can be used to create targeted content and improve SEO. 

Here are five keyword clustering tools worth considering:

Cluster AI

Cluster AI is an AI-powered tool that analyzes your website or content and identifies clusters of keywords that are related to each other.

This tool provides insights into the relationships between keywords and helps you to optimize your content for better search engine rankings.

WriterZen Keyword Explorer

WriterZen Keyword Explorer is a keyword research tool that helps you to discover clusters of related keywords based on search volume, CPC, and competition.

This tool provides valuable insights into the keywords that your competitors are using and helps you to optimize your content for better SEO.

Keyword Cupid

Keyword Cupid is a keyword research and clustering tool that helps you organize and group keywords into clusters for better content planning.

You can import your existing keyword lists and use their AI-powered clustering algorithm to group them based on relevance and search intent

Keyword Cupid also provides keyword suggestions and search volume data to help you identify new clusters and optimize your content.

Surfer SEO

Surfer SEO is a comprehensive SEO tool that includes a content editor, keyword research, and analysis tools.

Their Content Planner feature allows you to research and organize keywords into clusters based on their relevance and search volume. 

You can also analyze your competitors' content to see which keywords they are targeting and how you can improve your own content to rank higher in search results.


Serpstat is an all-in-one SEO tool that includes a keyword clustering feature. This tool helps you to identify clusters of related keywords based on search volume, competition, and user intent.

It also provides insights into your competitors' keyword strategies and helps you to optimize your content for better search engine rankings.


Keyword clustering is a technique that can be used to improve search engine optimization efforts.

By grouping related keywords into clusters, it becomes easier to create targeted content and optimize web pages for specific search queries.

This can result in improved search engine rankings, higher organic traffic, and better user engagement.

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