Keyword grouping, also called keyword clustering or keyword siloing, is one of the is one of the most popular strategies for keyword research in SEO currently, and for good reason. The days where 1 page ranks for 1 keyword are gone. Nowadays, one article can rank for 100s if not 1000s of keywords.
The technique consists of grouping semantically-related keywords together, so that you can organize your site into consistent content silos or keyword clusters. And more easily cover a niche in it's entirety without writing an article for every single keyword.
Following such an approach can help your site build authority and get more traffic from Google. But when dealing with thousands of keywords, figuring out how to group them manually can be overwhelming and time-consuming, if not impossible. Fortunately, there are a few tools that you can use to make that process frictionless. We’ve compared 6 free and paid SEO keywords grouping tools to make this list.
Optiwing's keyword grouping tool offers the best value for SEO professionals. It uses real-time SERP data to cluster keywords, preventing cannibalization, and improving rankings.
Put simply, if 3 or more of the same pages rank for a collection of keywords, then these keywords are grouped together. Optiwing makes the reasonable assumption that if 3 or more of the same pages can rank for a series of keywords, then you likely only need one page to target these keywords.
The tool works with keyword reports from Ahrefs, SEMrush, and Google Keyword Planner, or you can upload a custom keyword file (for example, one made from Google Search Console data).
We uploaded 1000 keyword from a SEMrush export file on the topic of "Snowboards". The results are available as soon as the job is completed in the browser which makes them very easy to scan, they're also available do download as a CSV (Microsoft Excel) file.
The Optiwing dashboard is intuitive to use, and since it uses real Google search results you can group keywords by device (mobile, desktop), geolocation, and use any language.
The tool took about 2 and a half minutes to group the 1000 keywords, which is quite fast considering that it uses real-time Google SERP data. You can see the results here. As you can see it gives tight and accurate clusters of keywords around a topic based on the search results.
Also includes a free SERP similarity checker tool, which is quite useful for comparing keywords to verify their relationships. You can also check the top 100 results for a keyword, which is quite useful for understanding the competition.
In terms of pricing, you get 100 free credits when you sign up to Optiwing, no credit card entry required. Pricing starts at $4.42 per 1000 keywords on a pay as you go (PAYG) basis. Credits never expire and there are no subscriptions to cancel, so no wasted money at the end of the month.
As far as entirely free keyword clustering tools go, ZenBrief is the best option in my opinion.
Many free tools use a Lemma-based approach (i.e. grouping keywords based on their root similarities - cluster, clusters, clustering - all have root similarities and would therefore form a group). ZenBrief uses an Natural Language Processing (NLP) methodology to understand the intent behind a keyword. This type of technique is a lot more accurate than Lemma-based clustering, but not as accurate as grouping methodologies that use live SERP data likeOptiwing.
The tool is also quite intuitive, you can upload up to 30k keywords at one time (as long as the file is under 1MB). ZenBrief then analyses the keywords with its NLP algorithm to form groups.
You can download each cluster separately or the entire grouping, which is quite convenient. Zenbrief’s clustering tool also organizes each cluster into separate columns.
SE Ranking is actually an all-in-one SEO software similar to Ahrefs and SemRush. But unlike their competitors they also have a powerful keyword grouping tool.
Like Optiwing, SE Ranking uses SERP data to group keywords. You can even choose the grouping accuracy by changing the minimum number of shared URLs to group keywords. Accuracy is defaulted to 3 URLs, but you can increase or decrease this.
You can also choose whether you want the tool to run a soft or hard analysis. Soft allows you to groups keywords that have similar URLs to the primary keyword, but not to each other. This can result in broader keyword groups that are not as accurate.
Quite a robust keyword grouping tool, so whats the downside?
Unfortunately, cost and pricing flexibility. To use the SE Ranking keyword grouper you need a full SE Ranking subscription, which starts at $49 per month. And then to use the keyword grouper, you have to additionally pay for every keyword you group ($4 for 1000 keywords, and $5 for 1000 keywords with search volume).
If you mainly plan to use the keyword grouper functionality then this is pretty expensive, and a monthly subscription on top of that can add up quick. But if you plan to use the software for all of it's functionality, it's not a bad deal at all.
One of the first keyword grouping tools on the market, Keyword Cupid has an established reputation for SEO.
Their keyword grouping tool also uses real-time SERP data to group keywords. Also claiming to use machine learning to identify SERP patterns for groups, and includes a confidence rating for how closely keywords are related.
It's not entirely clear Keyword Cupid's methodology for SERP analysis for overlapping URLs and hard and soft relationships between URLS and keywords. But even being a black box, it clearly offers quite accurate results.
Keyword Cupid offers the functionality of grouping keywords into topic silos, making it easier to define a site's hierarchy, and interactive mind-map visualizations. Here's what a output from Keyword Cupid looks like:
This is an example of what a topic silo looks like:
This is very helpful especially when creating an entire content strategy or site plan for interlinking pages.
Keyword Cupid is also on the pricier side, they offer four monthly subscription plans.
Their basic plan costs $9.99 a month and only includes 500 keywords, with additional keywords costing $20 per 1000 keywords, quite a far cry from the other tools on our list.
Their $49.99 a month plan includes 5000 keywords a month ($10 per 1000 additional), the $149.99 plan includes 20,000 ($7 per 1000 additional), and Enterprise plan including 80,000 keywords at $499.99/month, with additional credits costing $6 per 1000 keywords under this plan. Overall quite expensive and requires a monthly subscription, but a strong tool for building an entire site plan from scratch.
Another great SERP results based keyword grouping tool is KeyClusters.
KeyClusters also supports imports from Ahrefs and SEMrush and custom files.
KeyClusters uses a similar strategy to Optiwing and SE Ranking of comparing the top 10 SERP results for each keyword and identifying which keywords share the same results. These results are only available as a downloadable CSV file which is a bit inconvenient. This is an example of the results for the topic "Sewing Machine"
As you can see, the keywords are grouped into clusters and displayed in each row.
As far as pricing, KeyClusters also offers 100 free credits upon sign up. Pricing ranges from $9 per 1000 keywords to as low as $4.97 per 1000 keywords. A great tool, I would prefer if the results were available to view in the browser, and is strictly a keyword grouping tool, so no additional features, but a great tool for keyword grouping.
Another free keyword grouping tool to check out is Keyword Clarity.
I'm don't believe this tool uses NLP, it likely doesn't use SERP data because collecting SERP data is quite resource expensive to collect and just based off the results compared to other tools results. It most likely uses lemmatisation, which is an algorithmic process used to determine the intended meaning of a word.
Visually they look quite impressive, but are likely not as useful for targeting multiple keywords due to inaccuracies from lack of data from real-time ranking results. More useful for identifying sub-niches within a niche, or narrowing down topics than creating an entire content strategy in my opinion.
Keyword Grouping is a SEO technique that consists of grouping semantically-related keywords together, so that you can organize your site into consistent content silos or keyword clusters. It also helps generate insight on keyword search intent, and more easily cover a niche in it's entirety without writing an article for every single keyword.
Most keyword grouping software use one of two strategies, the most common and free methods generally uses Natural Language Processing (NLP) to help identify and group keyword with similar intent. NLP results are usually good at identifying keywords at a silo-level, but not at an article-level. For a more refined view of keyword groups, other tools use SERP data. Real-time SERP data helps identify overlapping URLs and keywords when keywords share similar or nearly identical search results, indicating similar search intent based on Googles algorithms. This methodology generally provides a more accurate measure of a keyword group.
Ideally, you’d want to create articles for every keyword group. However, this can be expensive and time-consuming. So, I believe in prioritizing keywords. If a keyword is high in volume, low in difficulty, relevant to your niche, and aligns with your business goals, it’s should be within your focus. Also building content silos and topical clusters is a great way to boost your SEO efforts.
The best keyword grouping tool currently is Optiwing keyword grouping tool. It uses real-time SERP data to cluster keywords, eliminating keyword cannibalization, and helping you rank for more keywords, while being the most flexible and affordable tool on the market.