Definition, metrics, and 5 tools to use

The Keyword Difficulty score has a significant strategic impact on website positioning.

Keywords are the absolute protagonists of every SEO strategy. That’s why, when you write content for the web, you need to carefully evaluate which ones to choose through strategic keyword research.

A thorough analysis that takes into account various parameters, such as the Keyword Difficulty metric, can help you understand how to plan your work and create high-quality articles well-positioned in the SERP.

As you continue reading, you will find further information on:

  • the definition of Keyword Difficulty;
  • the importance of Keyword Difficulty scores for SEO;
  • how to calculate KD and which keywords to choose;
  • the top 5 tools for measuring KD.

Mastering all the tools necessary to develop a winning strategy for website positioning is crucial. That’s why I recommend taking essential SEO courses to learn all the necessary skills and launch online projects while making the most of search engines. And a more advanced SEO Manager course to reach an even upper level.

What is Keyword Difficulty?

A definition of Keyword Difficulty, also known as SEO difficulty, is a metric that determines the difficulty of ranking in the SERP with a keyword.

Some keywords may perform better for your website than others, but to understand which ones are the most effective, it’s essential to know their difficulty score.

This numerical value is based on estimates and varies depending on the Keyword Research Tool used. Therefore, it’s important to consider this factor to understand how Keyword Difficulty is calculated.

In general, a result of 1 indicates a low level of difficulty, while a score of 100 corresponds to high difficulty.


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Why is Keyword Difficulty important?

The Keyword Difficulty metric is crucial for SEO as it is an essential aid in selecting the most suitable keywords.

Careful keyword research not only helps improve a website’s rankings in the SERP but also provides fundamental insights for your strategy.

keyword difficulty meaning

For example, long-tail keywords have lower search volumes compared to simple keywords, resulting in lower competition.

Trying to rank in search engines with a high-volume keyword and therefore high Keyword Difficulty may not be the most suitable SEO strategy. Just as choosing keywords with low KD doesn’t guarantee desired results.

For this reason, it is essential to understand how to choose keywords based on KD scores provided by various online platforms.

How to measure Keyword Difficulty?

As mentioned earlier, there are several Keyword Research Tools available to measure Keyword Difficulty, each considering different parameters. This is why KD scores for the same term can vary depending on the chosen platform.

These tools do not always provide accurate results, so it’s important to keep in mind that the results are estimates. Therefore, it’s advisable to compare multiple platforms to get a real idea of KD.

But which keywords to choose based on KD scores? Keeping your strategy in mind, you can opt for:

  • Low-difficulty keywords: You may receive more traffic from search engines quickly due to less competition.
  • High-difficulty keywords: This approach can yield long-term results as high competition makes it harder to rank high in SERPs quickly.

So, the choice depends on the type of SEO strategy you want to apply based on your business needs.

measure difficulty in keywords

A good practice could be to analyze the terms you have already ranked for and determine the Keyword Difficulty. This method could give you an idea of which keywords to choose in the future.

Another solution could be to use synonyms or related terms to the keyword, which may have less competition.

It’s essential to define the keyword strategy that you want to apply to your project.

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The 5 most used tools for analyzing Keyword Difficulty

On the web, there are numerous SEO platforms for analyzing Keyword Difficulty. Some may be easier to use than others. One common feature of many of these platforms is a keyword research tool.

Below, you will find information about the 5 keyword tools most commonly used for KD:

  • Moz Seo
  • Semrush
  • Ahrefs
  • Ubersuggest
  • SeoZoom

For each tool, I have highlighted the main features and the parameters used to measure keyword difficulty.

Moz Seo

Moz Seo is undoubtedly one of the most appreciated platforms for SEO analysis. It was probably one of the first to utilize the

Keyword Difficulty Score. It offers multiple features, among which Keyword Explorer stands out.

The Keyword Explorer tool is designed for keyword performance analysis and provides various metrics such as search volumes and who the main competitors are for a specific term. This can give you the opportunity to consider alternative keywords to add to your list.

Moz SEO collects and combines data from multiple sources into a single keyword database, which is systematically updated and monitored to provide the most accurate information possible.

Inside the Keyword Explorer, the Keyword Difficulty parameter is, of course, present.

moz seo keyword

KD is calculated taking into account the results of Page Authority (PA) and Domain Authority (DA) for those sites that have ranked on the first page of the SERP with a particular keyword. These are two Moz SEO metrics that Google does not use.

The Keyword Explorer tool allows you to combine the KD score with search volume and click-through rate (CTR) to find keywords with the highest chances of success.

Moz SEO is a platform that can also be used by less experienced individuals in optimization, thanks to its user-friendliness.

The platform allows you to group metrics according to keyword difficulty levels, volume, or click-through rate percentage to help you determine where to focus your efforts quickly and intuitively.

To use Moz SEO, you need to create an account, and once your email address is verified, you can start analyzing your keyword.


Semrush is a platform that has developed its own formula to obtain a Keyword Difficulty score as accurately as possible.

The difficulty level of a keyword is evaluated by the tool by examining the top 20 domains that appear in the SERP. The higher the value, the more competitive the selected keyword is and, consequently, the more challenging it is to rank among Google’s top results.

So, from an SEO perspective, this tool can be very useful for choosing the keyword to target and identifying potential market niches to enter.

keyword semrush overview

As with the previous tool, registration is required. In the free version, users can analyze up to a maximum of 100 keywords at a time.

In addition to search results, Semrush also provides some useful tips for getting more visits.

The results of Semrush’s Keyword Difficulty are divided into 5 categories:

  • Very easy from 0 to 14: in this range, there are excellent chances of ranking for new websites;
  • Easy from 15 to 29: there is some competition starting, but it is still possible to achieve high positions in the SERP;
  • possible from 30 to 49: there is further increased competitiveness for the keyword. I recommend proceeding with the creation of more structured and high-quality content;
  • Difficult from 50 to 84%: here, the challenge becomes more arduous, but positioning is possible with a strong SEO strategy. Quality content and backlinks are also essential to bolster the credibility of your content.
  • Very difficult from 85 to 100%: to rank in this range, you’ll need to undertake extensive on-page SEO, link-building efforts, and ADS campaigns to promote your site’s content.


Ahref is a paid tool primarily used by agencies and web professionals. This platform is primarily chosen for SEO analysis and link building, but it also provides valuable information about keywords. Ahref calculates Keyword Difficulty by considering an average of the number of domains linking to the top 10 pages on Google.

The Keyword Explorer tool in Ahref allows you to view the monthly search volume of keywords and provides related terms for your analysis. According to the platform, to rank on the first pages for high-difficulty keywords, you’ll need numerous backlinks. For keywords with low KD, the competition won’t be as fierce.

To calculate Keyword Difficulty with Ahref, input the keyword and navigate to the Phrase Match report, where you can customize parameters for your specific research needs. Unlike other similar tools, Ahref allows you to conduct organic keyword research on various browsers, including YouTube and Amazon.

With Ahref, you can also:

      • Monitor the growth of your site’s authority through backlinks.
      • Check for any factors that may penalize your site.
      • Verify the organic search results for your desired keywords.
      • Conduct a comprehensive analysis of your competitors.


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Ubersuggest is a widely used platform in the industry. Unlike the previous ones, it doesn’t require any registration to perform searches. However, in the free version, the number of searches is limited, and some functions are inaccessible.

Ubersuggest was created by Neil Patel, an internationally recognized marketer and web expert. This platform relies on real-time results provided by Google, including user query searches.

ubersuggest platform keyword analysis

Among the searchable results in the search, in addition to Keyword Difficulty, you will find other information such as:

      • Paid Difficulty: the difficulty of generating paid traffic;
      • Monthly search volume;
      • Cost per click (CPC).

An interesting feature of Ubersuggest is keyword ideas, which can provide valid keyword ideas among:

      • suggested
      • related
      • questions
      • prepositions.

By registering with Ubersuggest, you can also delve deeper into the analysis of your site by creating a New Monitoring Project.


SEOzoom is a highly regarded platform that allows market research and Keyword Research. It is a paid tool, but it offers a free trial for 7 days.

This platform distinguishes between Keyword Difficulty and Keyword Opportunity. As already discussed, the former is the metric that defines the difficulty of ranking with a keyword, while the latter indicates how likely it is to rank with that keyword.

To evaluate the KD, SEOzoom estimates based on the sites with the best positions in the SERP and their Zoom Authority, an exclusive metric of the platform that indicates the health and performance in Google searches of a specific website, essentially determining the value of your site.

SEOzoom also offers an Editorial Assistant among its features, a tool that can be very useful when it’s time to write an article and inspiration is lacking.

With this tool, you can receive valuable suggestions based on user searches in a specific industry or on a particular topic.


Measuring Keyword Difficulty is a crucial activity to perform before starting to write a blog article. Different platforms provide different values but keep in mind that they all rely on SERP results.

Therefore, let me give you a piece of advice: compare the various results provided by different tools and calculate an average score. This way, it will be easier to choose the most suitable keywords.

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