On-Page SEO

Keyword Clustering

Shahid Maqbool

By Shahid Maqbool
On Jul 4, 2023

Keyword Clustering

What Is Keyword Clustering?

Keyword clustering is a search engine optimization technique for organizing related search terms into groups.

It involves looking at a large list of keywords and finding which ones are similar in meaning and intent.

The purpose of keyword clustering is to make content creation and optimization easier. By putting similar keywords together in groups, you can content gaps in your website more easily.

This means you will know where you need to add content targeted at each group of terms.

For example, one keyword group might be related to mountain bikes. Another group might cover road bikes. This helps to create content focused on each bike type to provide more value to searchers.

In the end, keyword clustering aims to bring more targeted traffic to a site. It does this by helping to structure search terms so content can be optimized for them.

The result is that more relevant people find your pages in search engines.


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

Let's look at how keyword clustering works for a company selling sports shoes. First, analyze a large list of search terms about athletic footwear. From there, spot keywords that are similar and put them into groups.

For example, we might create clusters like:

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

These clusters allow us to see which keywords are closely related in meaning. Now when we make website content, we can use the clusters to keep things targeted.

For instance, we could write a blog article on the top trail running shoes for marathons. Or we might make a product page showcasing new high-top basketball models.

By organizing keywords into sensible groups, we help visitors find content specific to their search. If someone wants tennis shoes, we lead them to info on tennis, volleyball, etc.

Why is keyword clustering important?

Keyword clustering is important in SEO for several reasons:

Better organization

Putting similar keywords into clusters makes big keyword lists easier to handle. For example, a list may start with hundreds or thousands of terms. Trying to work with a list that long is confusing.

But once we group related words together, things get more organized. Suddenly we can see which cluster needs more content. Or which groups have gaps where new pages could go?

Looking at compact clusters allows us to spot places to optimize more quickly. We don't have to dig through a giant list of mixed-up keywords.

Improved relevance

Keyword clustering helps us create content that closely matches what visitors are searching for. When we group similar keywords, we see exactly what topics people care about.

This boosts engagement metrics like time on site and bounce rate. It also leads to more conversions in the end.

Enhanced targeting

Keyword clustering helps us understand what website visitors are really looking for. By grouping related terms, we see connections between keywords. This shows us the intent behind searches.
By separating keywords into clear clusters, we better grasp search intent. We know which topics and needs relate to each keyword group. This allows us to write targeted content focused on giving visitors what they want.

Competitive advantage

Keyword clustering can help us gain an advantage over competing websites. The key is finding holes in what our competitors cover related to keyword groups.

Finding out what others overlook around keyword groups gives us a prime place to stand out. We can corner certain keyword clusters with superior content that leaves competitors scrambling. This can provide sustainable search visibility through differentiation.

Types of keyword clustering

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

Hard clustering

Hard keyword clustering focuses on how search engines connect keywords behind the scenes. The key thing it looks at is - do different keywords bring up the same websites in results?

For example, the search terms "sneakers" and "trainers" may display lots of the same sites in the top 10 results. This shows engines relate these words closely in meaning.

In cases like that, hard clustering groups those keywords together. The idea is that similar results mean similar intent and topics around those terms.

This technique helps guide SEO in key ways:

  1. It shows which keywords can be optimized together on web pages rather than separately. If search engines link certain words already, we can target batches of them efficiently.

  2. It reveals how engines understand language and connections between search terms. We can use this info to structure our content and better meet searcher intent.

Moderate clustering

Moderate clustering takes a balanced approach to grouping keywords. It does not only look at search engine results, like hard clustering. Nor does it rely solely on keyword meaning, like soft clustering. Instead, moderate clustering uses both factors together.

This strategy first examines if different keywords bring back the same web pages in results. Next, it checks if those keywords are closely related in topic and meaning too.

For example, "sneakers" and "shoes" may share some search results. But "sneakers" is more directly related to keywords like "trainers" and "kicks" in terms of intent and specificity.

By weighing both conditions, moderate clustering creates keyword groups that are connected in two key ways:

  1. They produce overlapping search engine results

  2. They are similar terms in their own right

This two-pronged approach provides a robust view of relationships between terms. It helps ensure that optimized content comprehensively targets all related keywords in a cluster.

So moderate clustering balances raw search data with semantic meaning for effective SEO.

Soft clustering

Soft clustering is the most basic method for grouping similar keywords. It works by looking at the search results for each keyword and finding keywords that have a lot of overlap in their top search results.

The main limitation is that soft clustering only compares each keyword to the main or "centre" keyword in the cluster. It does not look at the relationships between all the different keywords within a cluster.

Lemma-based clustering

Lemma-based clustering groups keywords that have the same root word or "lemma."

For example, the root word or lemma for the words "running," "runner," and "runs" is "run." So this method would cluster those keywords together under the main root word - "run."

The advantage of using lemmas is that it can uncover connections between keywords that you might not notice otherwise.

Even though the words "running" and "runner" look very different at first glance, lemma clustering recognizes that they actually share the same root.

Is keyword clustering a positive signal for search engines?

Yes, search engines see keyword clustering as a good sign that a website is well-organized and has useful content.

By putting related keywords together in groups or "clusters," a website shows search engines that its content is connected by common themes and topics.

This type of semantic organization helps search engines better understand a website's structure and content focus.

It indicates to search engines that visitors who search for one of those clustered terms would likely find the website's content relevant and valuable.

Essentially, keyword clustering signals to search engines that a website has high-quality information on a specific subject.

Websites that use keyword clustering make it easier for search engines to match relevant search queries to appropriate website content.

As a result, clearly organised websites that use keyword clustering tend to be rewarded with better search rankings and visibility.

By optimizing for clusters of terms, they can attract more organic traffic across multiple related search queries. This can lead to higher conversion rates over time.

Also, by comprehensively covering a topic area, a website may be seen as a go-to place for searches within that niche or industry.

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.


keyword clustering is a really useful strategy for boosting search visibility. It works by organizing related keywords into groups based on shared themes and topics.

Creating content around these clustered keywords allows websites to optimize their pages for specific search queries.

The benefit of this technique is that search engines recognize the website as an authority within a subject area.

By effectively covering a topic in-depth, the site earns trust and rankings for multiple related terms.

Ultimately, keyword clustering leads to higher search traffic from ranking well for clusters of keywords.

This incoming traffic also engages better with the site because the content directly matches what they were searching for.

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